The rampant league leaders – who remain 23 points clear of Celtic – started Kemar Roofe up front in place of Alfredo Morelos as the Colombian began a three-match ban for his Ryan Porteous stamp.

But Saints boss Callum Davidson will feel his Betfred Cup finalists should have been playing against 10 men for the last 70 minutes after Roofe was let off with just a booking after catching Murray Davidson with a shocking lunge.

Gerrard named new signing Scott Wright on the bench but there no sign of Jack Simpson following his deadline day move from Bournemouth.

Millwall loanee James Brown came in for his first Saints start at right-back, with Craig Conway, Craig Bryson and Stevie May also refreshing a team that had to dig deep to fight back from two down to beat Kilmarnock on Saturday.

Had Rangers been sharper, the visitors would have been three down at the break this time.

Gers' first golden chance came in the 12th-minute as Joe Aribo knocked down Connor Goldson's 40-yard ping for Ryan Kent. The winger shifted the ball onto his right foot in one effortless movement but got his finish wrong as he pushed it a whisker wide.

Saints were not afraid to have a go, springing forward on the counter in the early stages.

They were given a little help, however, when Filip Helander got himself in a muddle trying to shield the ball away from May in the box. Bryson nicked possession but thankfully for Rangers' Swedish centre-back, the angle was against the midfielder and Allan McGregor was able to block at the front post.

Gerrard made an appeal for consistency to be applied to the SFA's disciplinary proceedings this week, hitting out after Hibs defender Darren McGregor escaped punishment for trampling on Glen Kamara while Morelos found himself banned retrospectively for the second time this season.

David Munro kept up the referee's run of missing big incidents as he let Roofe off lightly after his ugly challenge on Davidson, who would later limp off suffering with the after-effects of the tackle.

Roofe's touch had been off all night and it was while chasing another loose ball that he planted his studs into the Saints veteran's ankle.

And his finishing was no better, wasting a big opportunity in the 32nd minute as he lashed wide from six yards after Aribo's sublime footwork saw him wriggle past Jamie McCart down the left.

Saints were proving hard to break down yet Rangers still had time to see another opening slide before the break as Goldson miscued from close range after Tavernier slung a beauty of a free-kick in behind the visitors' back line.

But Rangers did get the breakthrough within seven minutes of the restart after stepping up the pressure.

Ryan Jack fed Hagi wide on the right and the Romanian took the initiative, driving back across the edge of the box before angling a firm low finish back beyond Zander Clark for his fifth goal of the season.

The job was not done, however, and McGregor had to stay focused as Bryson twice threatened to spoil Gerrard's night.