Sunderland boss Martin O'Neill says John O'Shea has returned to his best.
O'Shea was outstanding for victory at Southampton.
"He (O'Shea) will be important against Manchester City," O'Neill said. "I think he felt that last week against Manchester United, his old team, he wanted to play really well.
"Not that he's got anything more to prove to Man United, he's had his career there.
"He might have been a bit disappointed, particularly in the first goal we conceded. But he's made up for that."