Manchester City boss Roberto Mancini is calling for more from Samir Nasri ahead of Sunday's clash with his former club Arsenal.

Nasri has failed to command a regular spot in Mancini's impressive side since his high-profile £24million move from the Gunners in August.

The France international showed glimpses of his talent as he made four successive starts recently but he was back on the bench as the Barclays Premier League leaders lost at Chelsea on Monday.

The 24-year-old faces stiff competition for a place in star-studded City's midfield but Mancini has no doubts about his ability.

Mancini said: "In my opinion Nasri is a champion - a top, top player.

"I think he can do more but when you change teams you can have a problem.

"At this moment his confidence is maybe not very good because he didn't play against Chelsea but if he plays Sunday he has a chance to show us.

"I would like Nasri to play better, because he is a really good player."

Mancini similarly demanded improvement from winger Adam Johnson earlier this season despite some impressive performances from the former Middlesbrough man.

Mancini believes players of their talent should be delivering to high standards consistently, yet he accepts he cannot always accommodate them.

He said: "When you play with two strikers and Samir and (David) Silva, you have more chances because you attack.

"But there will be some moments when it is difficult to support all the offensive players all the time.

"I need to change sometimes but Samir is a good player."

Nasri's recent run in the side included the Carling Cup quarter-final victory at Arsenal, during which he was barracked throughout by home supporters.

He responded with a superb performance in the 5-1 thrashing of Norwich and Mancini now wants him to step up again, especially with midfield linchpin Yaya Toure heading to the African Nations Cup in January.

Mancini said: "I think we will lose an important player but I hope Samir can play more games at a higher level.

"He is a top player. Every game a player like that should contribute."

The 2-1 defeat at Stamford Bridge ended City's impressive unbeaten start to the campaign.

They now face a tough task to get back to winning ways as the Gunners visit the Etihad Stadium on a fine run of form.

Arsene Wenger's side have won seven of their last eight matches and their talisman Robin van Persie is the league's top goalscorer with 15.

Mancini said: "Van Persie is an incredible player.

"He is like (Sergio) Aguero, (Edin) Dzeko, Mario (Balotelli) - scoring a goal every game.

"At this moment he is very good, like Arsenal. At this moment they are playing very well."

For all their domestic dominance this season, City could be second come kick-off if Manchester United beat QPR earlier in the day.

Mancini said: "At the moment, us, United and maybe Tottenham are the three teams that can fight for the title.

"But the season is long. Chelsea, Arsenal and, maybe, Liverpool could also try.

"The season is hard. We have a lot of games to play in the next 40 days."