Armstrong's second just after the half-hour ended the game as a contest, and Wycombe's misery was compounded early in the second half when a professional foul earned Darius Charles a straight red card.

Derrick Williams got in on the act midway through the half before Armstrong rounded off the scoring late on – his fourth goal in the space of a week.

The Chairboys showed plenty of heart but the contest was a mismatch from the moment Dolan's trickery brought about the penalty.

It marked a nightmare return to Ewood for Gareth Ainsworth, a lifelong Blackburn fan, and his side are still searching for their first goal and point.

Tony Mowbray was without Lewis Travis, but Dolan made his senior bow – one of two changes.

Wycombe named an unchanged side, and forced an early chance when Thomas Kaminski made a mess of a corner, but David Wheeler's shot was blocked.

Blackburn's first meaningful attack resulted in the opener when Matt Bloomfield clumsily brought down Dolan.

Armstrong stepped up and clinically dispatched the penalty into the right corner.

After winning the penalty, Dolan marked his first start with a goal in the 20th minute as Rovers cut through their opponents. Lewis Holtby's pinpoint pass gave the teenager a clear sight of goal and, though Ryan Allsop repelled the shot, he showed excellent composure to slide the ball under the goalkeeper.

Joe Rankin-Costello thumped the post moments later but it was only momentary respite as Rovers netted a third in the 33rd minute.

Blackburn ruthlessly highlighting the gap in quality with a counter-attack that left Wycombe hopelessly outnumbered, a move rounded off when Rothwell's cross was tapped in at close range by Armstrong.

Wycombe's nightmare afternoon worsened in the 57th minute when Charles was shown a straight red card for bringing down Armstrong, who would otherwise have been through on goal.

It was no surprise when a fourth arrived in the 67th minute, when Williams tapped home after Allsop had superbly kept out Rothwell's piledriver.

And Armstrong capped a perfect afternoon seven minutes from time when John Buckley's inch-perfect pass put him clean through and he calmly rolled the ball beyond the goalkeeper.

He could have had a fourth before the end when a routine long ball set him clear again, but Allsop brilliantly denied him.