The Premier League leaders have stuttered since Christmas, suffering a shock 1-0 loss at Sunderland after a frustrating goalless draw at West Brom. City still top the table from Manchester United on goal difference but face another tough test as Liverpool visit the Etihad Stadium on Tuesday night. De Jong told City TV: "We win with each other, we lose with each other. "We have to take this one on board, discuss it and see what went wrong and just go on to the next game." That City have failed to score in their last two games comes as a surprise after they hit the net 53 times in their previous 17 games. Roberto Mancini's men had spells of dominance at The Hawthorns on Boxing Day and the Stadium of Light on New Year's Day but they found both opponents in resolute mood. De Jong added: "In most of our games we have dominated possession. "That doesn't say anything if you don't score a goal. Then you can't win, obviously." De Jong himself made his first start for City since November in the last-gasp defeat to the Black Cats. The 27-year-old Holland international was a key member of last season's FA Cup-winning side but has fallen down the pecking order since a spell out in August and September with a foot injury. Mancini accepts he may be frustrated with the situation but the City boss insists the tough-tackling World Cup finalist remains an important member of his squad. The Italian said: "Nigel had too many problems when we started the season, two months off for injury. "After this the squad played a different system with two strikers, two offensive players like wingers and only two midfielders. "For this reason Nigel did not play a lot of games but he is still an important player. There is no change in this situation. Now he can play. "I think it is normal that one player, when he doesn't play, is frustrated. "For him it is difficult but now we are playing five games in 16 days and we need our players."
