After the match, the boss lamented his side's inability to build a more commanding lead but praised the Black Cats for resisting what had seemed an inevitable defeat, stating his opinion that Sunderland "won't have any problems" and "have a reasonable team."
"A lot of our football was fantastic and some of our interchange play was terrific," Sir Alex told MUTV. "I don't know if we relaxed when we went 3-0 up or if Sunderland got a grip of the game, but towards the end they played very well and could have scored two or three goals.
"Some of our play was fantastic and we should've scored more. Tom Cleverley's goal was a marvellous piece of interchange play, a first time finish and a really superb goal which epitomised the way we were playing at that point. I'd no complaints for an hour and it was wonderful to watch.
"We don't pick out Robin van Persie's runs as well as we should - his movement is great and he kept them on the back foot. But Wayne could've scored three of four goals, he hit the bar and missed two or three chances in the first half. But he got one which is important as it keeps his run going."