Swansea sub Luke Moore's 83rd-minute winner allowed Manchester United to leapfrog their neighbours and go top of the Premier League.And City's frustrations boiled over as two of their key stars began shouting at each other in the tunnel at the interval.Roberto Mancini's men had taken a long time to get going against a fired-up Swansea outfit.Balotelli and Toure were deep in conversation as they left the pitch at the break and again when they reappeared for the second half.But they had an angry exchange after entering the tunnel, even though Mancini insisted he knew nothing of it.The Italian boss said: "No, I don't know anything about this."City stayed in Portugal for two days after their 1-0 Europa League defeat by Sporting Lisbon.And their manager admits they are feeling the effects of a long season, with a quarter of it still to go.Mancini added: "The last four days have been very difficult for me."Maybe we were tired at the start. This is normal after seven months of the season, as we are playing three times a week."We've lost two games in four days and this is a bad moment for us."Swans chief Brendan Rodgers saluted his heroes, who were good value for a famous victory.He said: "Sometimes you get results where you take on the big guns of European football and you win the game 1-0 and are hanging on. But we were the better side in this one."Rodgers is sure City can hit back in the title race, adding: "There are 10 games to go and there will be more twists and turns."This was always going to be a tough game for Manchester City but there are enough games to play and enough changes can happen."I just want to finish the season with a sprint over the finish line. Our players are loving every moment of this journey after being the team everyone fancied to go down."