Danny Welbeck. The breakthrough was almost provided by an unlikely source when Patrice Evra's ambitious overhead kick dropped wide and fellow full-back Rafael also had a decent chance but shot tamely at Schwarzer with his left foot.
After a penalty shout for handball against Stephen Kelly was turned down by referee Michael Oliver, the deadlock was broken three minutes before the interval. Ashley Young's dangerous cross went over Brede Hangeland's head and under Riise's studs. Evans pounced to show great awareness to tee up Rooney and the striker gleefully smashed home, immediately acknowledging the Northern Irishman's part in the goal.
Relaxed, the Reds started the second half in complete control but were unable to find another way past Schwarzer. Giggs' excellent pass released Valencia but the Australian keeper saved well, with Riise getting to the rebound first to stab it behind to safety.
Aaron Hughes survived a nervous moment when dealing unconvincingly with a Rafael centre before a trademark curler from Young brought the best out of Schwarzer, who dived to parry. Damien Duff made a vital block as Fulham continued to smother many of the United attacks and Sir Alex decided to shake things up in attack by replacing Welbeck with Javier Hernandez.
The champions kept knocking on the door but Giggs dragged a left-foot attempt well wide and Schwarzer made a superb double stop to keep out