Caught out by Rooney's phenomenal strike, losing his balance and bearings as he stumbled back to his line. Looked nervy after that, but made several good saves from Mata and Kagawa.
Does not have the pace to deal with the running of the likes of Kagawa and Rooney, but it was not his fault he was left so unprotected by the midfield in front of him. Could not do much more than usher United's forwards into tight angles away from goal.
Dragged wide by Young, isolating Tomkins to his right, and did not really ever put a lid on the winger's deliveries into the box.
Really struggled to cope with Rooney. Far too easily shrugged off the ball before the striker struck his first, and also could have been punished for a horror pass in his own half.
Never asked many questions of Kagawa's willingness to track back and his distribution was not particularly impressive either.
West Ham's most dangerous player, he attacked Rafael effectively early on and was responsible for most of Carroll's best service. Switched flanks after half-time and faded.
Struggled to make an impact on the right flank and was ponderous when he did receive the ball in dangerous areas. Replaced by Jarvis early in the second half.
A passenger for the most part. Never got to grips with Mata.
Worked hard to track back and help his defence only to see his attempted clearance cannon off Rooney's shins and find the back of the net. Got on the ball more than Taylor, but to no great effect.
Never got in the game. His usual link-up play with Carroll did not materialise.
Got on the end of a couple of crosses to test De Gea but for the most part he spent his time flinging himself at high balls in completely unthreatening areas. His effort can't be faulted, but he might do his team more good if he was slightly more subtle about it.
No difficult saves to make and while his defence was occasionally unnerved by balls into the box, he generally dealt with everything thrown his way well.
Struggled to get to grips with Downing early on and saw yellow as he resorted to cynical fouls, but improved in the second half.
Can take satisfaction from a strong display with the back-up left-back to one side of him and a central midfielder to the other. Carroll got little change out of him.
It seemed a risk to rest Evra with so many of United's first-choice defenders already missing, but Buttner performed strongly and snuffed out the threat posed by Diame.
Added some much-needed bite to the United midfield, creating one excellent chance with a typically well-timed bit of pressing in the West Ham half.
Behind the superb displays from Rooney and Mata was a much improved outing by Fellaini. Finally showed his ability to use his stature and strength in the centre of the park, and kept it simple in possession.
Always offered his team-mates an option on the right and although his crossing remained inconsistent, he played a part in many of his team's most dangerous attacks.
Was never going to be comfortable against Carroll and lost out in some aerial duels but did as much as he could to prevent the striker having any clear opportunities at goal.
Spurned a couple of good chances, but his runs off the ball and creativity with it were promising and he has done enough here to merit a longer run in the side.
His first goal ranked up with the best of his career, and his second with the worst. However they ended up in the back of the net, the most encouraging thing was the inventiveness and confidence with which he played as the lone striker.
So much more effective in a central role. While Rooney will grab the headlines, Mata was arguably the outstanding performer, combining with Kagawa in particular time and time again.