Substitute Ji Dong-Won scored the winner with the last kick of the game, with the striker finishing off an effective counter from the hosts by rounding goalkeeper Joe Hart and tapping the ball into the empty net.
O’Shea praised new boss O’Neill and his stirring half-time team talk that seemingly inspired the Sunderland players to keep their heads high and go for the win despite dominant spells for City.
He told Sky Sports: “The manager spoke at half-time, he said 'we don’t want to lose this game 1-0 and people say we did okay, we kept them quiet'. Credit has to go to him for giving us that bit of belief to say we weren’t going to lose this game and he made sure of that at half-time, the lads were fantastic.”
“City are a great team and [created] a hell of a lot of chances as well, but as a unit we were great today,” he added.
Asked about whether he would be getting messages of thanks from his former team-mates at Manchester United, O'Shea added: “Possibly, possibly. But that’s one of those things, they had a disappointing result yesterday and this will have cheered them up a bit, but more importantly for us it was a fantastic result. The way we played today shows the character in the team.”
Fellow Black Cat Lee Cattermole was also delighted with the performance of the team and insists the win came as a result of keeping the belief that they could take all three points.
He said: “Start to finish we knew we’d have to work hard as a team and match all the runners and do all the hard work, but I think when we had the ball we played as well. It was a tough game to come through.
“I think you’ve got to be organised as a team, but you’ve got to have that belief. I think we’ve got that bit of spirit when we go into a game and believe we’re going to win.
“We’ve had a lot of bad luck at the start of the season, I think we were playing the same as we are now, but things weren’t happening. There were some big performances, you have to have a team of nine eight out of 10s to beat City today and that’s what we had today.”
Micah Richards missed a superb chance to put City in the lead just moments before Ji stole the show with his winner, but Cattermole admitted he was surprised to see the defender’s header hit the bar and also praised goalkeeper Simon Mignolet on his return from injury.
He said: “Yes [he thought Richards would score], they’d had chances all game and I think fair play, Simon has come back and I thought he was magnificent today to come back on only 48 hours' notice.”