Manchester City boss Roberto Mancini admits Samir Nasri's inconsistency makes him wish he could 'punch' the Frenchman.
Nasri's ability has never been in doubt, with City having splashed out £24million to secure his services from Arsenal in 2011.
He impressed during his debut season at the Etihad Stadium, as he helped to land the Premier League title, but has been criticised at times this term for an apparent lack of effort.
Nasri was, however, back to his best during a crushing 4-0 victory over Newcastle United on Saturday and Mancini is confused as to why the 25-year-old cannot perform to those levels on a more regular basis.
He said: "I would like to give him a punch, because a player like him should play like this always.
"Every game. Maybe one game sometimes he can play badly.
"I don't understand what was different. I can't understand how a player with his quality doesn't play like this every game.
"The second year is always difficult to win the title again. And sometimes the player can think it is enough to play 50 per cent. We've probably had this problem this year."