Live Commentary: Novak Djokovic vs. Marin Cilic - as it happened

Good evening everyone and thank you for joining us for our live coverage as world number one Novak Djokovic takes on current US Open champion Marin Cilic in the semi-finals at Flushing Meadows.

The winner of tonight's clash with face either five-time champion Roger Federer or Stan Wawrinka in the final, with those two doing battle for their place in the conclusion of the showpiece straight after this contest.

Cilic will be confident as the holder of the title, but it has not been the easiest of routes for the Croatian to get to this semi. Cilic had to fend of serious competition last time out against Jo-Wilfried Tsonga, who battled back from two sets down to almost edge past last year's winner.

Djokovic has also had some tough tests in the build up, although the Serbian does have a tremendous record against Cilic to fall back on. As it stands, Novak has beaten the Croatian in every one of their competitive matches. Djokovic has won all 13 without being beaten.

Recent history favours Djokovic too. Novak has not dropped a set to Cilic since they faced each other during the 2014 Wimbledon quarter-finals. Djokovic most recently claimed victories over Cilic during the Monte-Carlo Rolex Masters and this year's competition at SW19.

Djokovic knows this event all too well, and has been in the final on four of his past six appearances. One thing that will bug the 28-year-old is that he has not won the US Open crown since 2011.

One thing that will particularly please Cilic, however, is that he is currently on a 12-match winning streak at the Grand Slam event in New York.

Cilic has been speaking about the prospect of facing Novak in the run-up to this contest. Here is what he had to say to ATP: "I'm trying to approach every match as a new one. Of course when you look at the statistic that he won that many matches against me, it doesn't go in my favour. But when you're coming into the match it's always going from zero, so it's a new match. It's a different stage and I'm feeling good here on the court."

Despite his obvious dominance in their past encounters, Djokovic has insisted that he remains wary of his looming semi-final opponent: "He won his first Grand Slam title last year in New York. He hasn't lost a match in 12-13 matches in a row [here], so I'm sure that he feels confident. He's had a couple of five-setters already in this tournament. He has a big serve. I think around 30 aces he had [in the quarter-finals], so the serve gets him out of trouble. I know him very well. I have played with him many, many times. We are great friends. A great guy. I know what to do and I'm hoping I can execute the game plan and play my best."

How will tiredness play a part tonight? Cilic has had to come through a few five-set games and that could get hold of the Croatian a little later in tonight's fixture. Djokovic has seen a good amount of tennis after being dragged to a couple of four-set games, but he appears in good shape going into this match.

Cilic appeared to be playing some smart tennis in the early stages against Tsonga as he picked his opponent's game apart. However, as the game drew on the current champion appeared to falter on his supposedly dominant first serve and Tsonga battled back to put him under real pressure. If he gives away the chances he did in that game tonight, this could easily be all over within three sets.

Djokovic is well aware of Cilic and he will be looking to exploit every weakness available. In previous encounters, Novak has loved to push down the line and also look to put pressure on with his returns from service. Cilic has a huge serve on him at times, but it is whether he is able to get it right tonight that will make the difference.

Both players are now arriving out onto the court at the Arthur Ashe. This is all setup to be a wonderful spectacle!

Cilic has had a bit of a dodgy ankle of late, and it will be interesting to see how he holds up given that he had to come through five sets against Tsonga in the quarters.

People have been queueing for hours outside of Ash ahead of this fixture. We are due a full house today. The stands are now starting to fill up quite quickly as the players run through their warmups.

Novak is usually ice cool in these events, but he has looked a little agitated in some of his games at this tournament. The world number one has often been captured uncharacteristically shouting after losing points, as well as go through the odd racket or two. Could that be something Cilic tries to exploit?

Here we go then, Djokovic to serve...

Decent work from Novak early on as he forces Cilic into two opening forehand errors. The Croatian comes back when Djokovic comes unstuck unforced, but he soon seals things with some offensive work on second service and a standout ace.

BREAK! Novak shows his quality already on the return as he sends one straight back down the middle to cramp his opponent. Fantastic work again from the Serb, who stretches before profiting from a poorly-worked smash from Cilic. Wow.. More stunning work sees Novak cramp his man once more, but this time it is from way deep. Triple break point! Djokovic claims the break when Cilic pings long from a rally.

A fairly tame return finds the net for Cilic first up, and he is under the cosh straight after as Djokovic forces him too deep on the baseline to make the return. Novak perhaps tries a little too hard with a forehand across the court, although he finishes things next with strong second service.

BREAK! Back on service, Cilic is undone by a huge one straight back down the line from Djokovic: a real beauty of a shot from the Serb! He still cannot find his range and Djokovic sends one deep, resulting in a tame return into the net. Djokovic offers up a free point into the mesh, before firing a return long at 30-30. Novak has all the answers, however, as he powers something strong into the chest of an on-rushing Cilic. The Serb then takes his second break in a row as the Croatian double faults. This could get ugly, folks...

Things aren't quite working out at the moment for Cilic, who chucks another return into the midway point. However, the current champion comes back strong to swipe across the court and draw level. Parity does not last long, though, as Novak throws a killer serve down the middle to force a winner, before backing it up with a deep serve to move to game point. It's over pretty quickly as Cilic cuts a poor return wide of the mark.

SET! Novak isn't missing a thing as it stands, as he booms a marvellous return deep to catch out his opponent. Cilic comes back when Djokovic fails on the forehand. The abuse continues, though, much to Cilic's dismay when he canes another rally wide of the line at 30-15. Nice! An ace brings the Croatian level, but another class return from Novak takes him to a third break point in three games.

It does not work straight away, this time as Cilic responds with a drop shot to bring deuce. Novak is straight back onto the pace when he forces the champion wide for another set point, only for deuce to fall again. Wait there, another poor wide one hands set point back to the Serb and he eventually nabs it by cutting Cilic in half with pure power down the middle. That, I must say, was a tad embarrassing: a blank for the Croatian...

Novak seems comfortable back on service and he marches into a 30-0 lead without resistance. Another booming backhand down the line does for Cilic, who has the lights cut out next up when Djokovic forces him to return beyond the baseline.

A little better from Cilic to start as he scores early, but some brute force from Djokovic has him back level after some great footwork and placement over the net. The scores move when Novak invites the smash, only for Cilic to stifle himself at 30-30. Hmm a double fault gives Novak another break chance, which is soon snatched away following a wonderful Croatian ace. Cilic eventually works towards his first game point of the match, only for another mistake to allow deuce. The current champ eventually sees out the hold to claim his first game of the contest, weird.

Pretty efficient stuff now from Novak, who advances to 40-0 unchallenged with some accurate service. Djokovic completes a hold of his own when Cilic throws back a poor forehand to concede yet another unforced error. They are mounting up already tonight!

BREAK! Novak is left frustrated by some poor return work, although he is given a fillip when Cilic drags wide without much pressure. Djokovic receives some help from the net, leaving his opponent to cut a return wide at 30-15. Scores are level again when Novak tries something cheeky from deep, but he achieves break point when Cilic pings 15 feet beyond after an impressive rally. Another break arrives when the Croatian chucks out another unforced error.

An impressive hold follows for Novak, as battles forward with strong work on his second service game. Cilic pushes yet more poor attacking shots wide of the lines, leaving Djokovic to play out the game with relative ease. The Serb is in complete control now...

BREAK! The backhand falters for Novak a little back on Cilic's serve, but his opponent then fails with one of the worst chips I have ever seen in the history of tennis. Cilic moves back in front when Djokovic is forced into an error of his own, but they do not call him the world number one for no reason! He comes straight on the attack with a wonderful forehand winner to tie the scores. More mistakes from Cilic arise... What's that? Another break? Okay then... Novak completes the game when Cilic double faults for the second time.

SET! It looks as if Cilic might just push towards a break point, however Djokovic comes back with a running whip to claim the point just before the baseline. An ace then pushes the Serb into a lead, and he completes the hold with a stunning forehand whip to take his second set. Pure brilliance we are witnessing this evening.

Here we go then, can Novak wrap this up in three straight sets?

BREAK! Poor Cilic, he cannot do a thing right at the moment. He produces a forehand error on his own serve, before continuing into the net to go 30-0 behind. An ace gives him a chance at 30-15 and he takes it as Novak comes up short on a simple exchange. Continued poor return from Cilic sees him in trouble at 40-30... and as you guessed it, Djokovic pounces to grab with exquisite rally placement.

The Serbian march of progress continues unabated as Novak cruises into a 40-0 lead back on his serve. The hold zips by without notice when Djokovic fools Cilic with a delightful lob from the net.

Finally some fight from Cilic as he wraps up one of few holds following some improving service work. Djokovic is only able to register the one point on this occasion, leaving his opponent to finish things off with a forehand winner that gets the whole crowd applauding. It is more of a sympathetic one than anything too mean.

BREAK! This must be really frustrating for Cilic, who again fires wide off a really simple return. He just cannot plant much inside the lines tonight... Novak moves to 40-15 as the Croatian makes two errors (shock!), but his Serbian opponent cannot wrap up the game when he double faults. Cilic is presented with his first break point of the contest, and he takes it with a deft chip following a standout rally. Finally something for the champion to cling to...

BREAK! Not so fast... Djokovic breaks back as Cilic continues his habit of creating some of the silliest errors know to man. Novak completes his mini comeback at the first time of asking following a masterful return and a forehand winner.

It is a fairly simple hold for Novak, who has to revert to some adroit play on his second service at times. An ace and brutal forehand help him on his way to a 40-15 lead, before the game is capped off with the truest of backhands straight down the line to catch Cilic cold.

BREAK! Did that just happen? Djokovic looks stranded at the net, but he cuts straight back across the mesh to leave Cilic stranded tight on the other side. The poor side of Cilic's game returns to haunt him once more with another unforced bogey, and Novak capitalises to take it to 40-0 when the Croatian shoots into the stands. Djokovic takes the break at the first time of asking as Cilic throws a limp return into the middle. The world number one is now serving to move into the final.

GAME, SET & MATCH! Great placement allows Novak to open up the court and stretch Cilic deep and wide with a forehand. The Croatian tries something too cheeky from the baseline and he then falls further behind at 30-0. A backhand volley over the net on the spin from Novak produces something magical for the cameras, and he then seals easy progression after a long, looping error return from Cilic. That was a true masterclass from Novak, stunning stuff on Ashe...

What have we just witnessed? True demolition work from Djokovic to secure his place in the final of the US Open. Cilic was only able to grab three games across three sets at Flushing Meadows. Novak is looking a touch embarrassed at his dominance during his post-game interview.

Djokovic has suggested that Cilic was carrying a troublesome ankle problem during the game, but I am not so sure that an injury had too much of an impact tonight. Novak was just evidently too good for the Croatian. I think those remarks during his interview were purely for empathetic reasons.

Cilic made far too many unforced errors in that game. You cannot afford to do that against anyone in a semi-final, let alone against Djokovic when he is playing arguably his best tennis of the tournament.

So Novak moves into the final with consummate ease... The world number one will face either Federer or Wawrinka, with the pair doing battle next up on Ashe. That is going to be all from me this evening. Goodnight!