The scoreline flattered the visitors - Bayer got off to a wretched start and simply couldn't cope with United's pressing as they dominated midfield in a way they haven't for a very long time, thanks to Marouane Fellaini with a little bit of help from Shinji Kagawa. The Bundesliga side could barely escape their own half, and when Wayne Rooney opened the scoring, the goal had been coming. Patrice Evra appeared to be offside collecting a ball down the left, but took advantage of the linesman's leniency to put in a cross for Rooney to volley into the net.
United had several further chances in the remainder of the first half, with Kagawa sending a cross and then a shot narrowly wide across the goal, and Robin van Persie being denied by Emir Spahic taking the ball of his toe after the Dutchman had cut inside onto his left foot.
Leverkusen had to improve a lot to get something from the game after half-time, and although they failed to put any real pressure on United, Simon Rolfes stepped up to their rescue, curling a superb shot from distance past David de Gea to give the visitors an ill-deserved equaliser.
United weren't long in responding, however, and Robin van Persie soon followed up with a majestic finish, gliding the ball over Bernd Leno with a superbly-weighted sweeping volleyed lob. Leverkusen advanced in search of a second equaliser, but were soon undone after Spahic, up until that point excellent, made a horrendous misjudgement of a high ball to allow Rooney through on a one-on-one to beat Leto with a dummied finish.
United were not as dominant in the first half, but were still keeping Bayer well out of the game. Shinji Kagawa had looked to be having one of his best games in some time, but disappointingly faded in the second half. One possible problem that is likely to arise again was that Fellaini and Michael Carrick had both started, and there were a lack of players on the bench capable of controlling and pressing in midfield. But a classic United counter-attack completely killed the game dead shortly afterwards, Wayne Rooney escaping through the middle of the park and teeing up Antonio Valencia to unleash a booming low strike into the bottom corner.
Bayer pulled one back shortly afterwards, with Lars Bender smashing a header off the bar from a corner which was diverted home by Omer Toprak, cutting United's lead back to two goals. Van Persie then suffered a bewildering miss as he somehow managed to put the ball wide of the far post while getting on the end of Valencia's cross two yards from an open goal.