Manchester City manager Manuel Pellegrini believes his side must improve if they are to reclaim the Premier League title this season. City travel to Newcastle on Sunday looking to move back to the top of the Premier League. They have improved on their early-season form, which led them to away defeats at Cardiff, Aston Villa, Chelsea and Sunderland. Now they are on a nine-game unbeaten run in the Premier League and are just one goal shy of their total for all competitions last season. Nevertheless the Chilean boss called on his side to raise their game still further as the title race hots up. "We are in a very good moment, but we are just in the middle of the season," he said. "It will be very close until the end of the year with four or five teams. It is very important to win titles, not to make mistakes in important games. That is why every game is a test for all of us. It doesn't matter against who we play Manuel Pellegrini "I hope we can do better. It is very important to win titles, not to make mistakes in important games. That is why every game is a test for all of us. It doesn't matter against who we play." Pellegrini said proving City's strength in depth would be an important factor in their title bid. "It is important for the whole squad to see we can change names and we can continue playing the same way." City's local rivals Manchester United, the reigning champions, are currently 10 points behind them and 11 points off the lead but Pellegrini does not discount them in the race for the title. "We are absolutely sure Manchester United will continue fighting to the end, because they are used to doing it. "Liverpool and Everton are teams that will continue fighting to the end. They play very well so maybe five or six teams can fight for the title." Pellegrini has no new injury concerns, but Newcastle are set to be without several key players as they look to improve their woeful record against City. The northeast club have lost their last nine games against City, a team they haven't beaten for more than eight years. Their task on Sunday is likely to be made harder by the absence of captain Fabricio Coloccini, who is out until late next month with knee ligament damage, and fellow defender Mathieu Debuchy, who is suspended. France midfielder Yohan Cabaye (Achilles) and Italian defender Davide Santon are also doubtful, but Newcastle manager Alan Pardew is boosted by the return of first-choice goalkeeper Tim Krul following a shoulder injury. Newcastle have lost their last three games, but remain a healthy eighth in the table following a fine run of results in November and early in December. "We've had a very good first half of the season in terms of our league performance so we come into this game in good fettle, albeit missing a couple of players," said Pardew. "It's important when you come up against teams of this quality that you perform consistently throughout. You can't afford to start slowly or to switch off for a second, because they're a great team. If I put my neutral hat on, they [City] should win this game, but we've upset some of the top teams in this division, and we'll hope to pose City problems. "Injury-wise, Yohan trained on Tuesday and Friday, but Davide Santon hasn't trained and he's a doubt."