William Gallas sounded like a captain after Tuesday's win over AC Milan but I'm not convinced he's started acting like one. Gallas was rightly full of praise for his Arsenal team-mates, but if he's to lift a trophy at the end of the season he'll have to mature. Which sounds daft, since he's 30.

In the Barclays Premier League title run-in and the later stages of the Champions League, there will be moments when the captain's contribution can be the difference between defeat and victory. I'm not sure that Gallas can inspire in the manner of Steven Gerrard for Liverpool or like Roy Keane did for Manchester United - either by what he says or what he does.

At the San Siro, Gallas talked about “my team” and “my players”, but does he really hold the respect of the dressing-room? It's hard to have faith in someone whose mood swings from one game to the next. On the eve of this week's match he gave an interview that went into detail on Theo Walcott's potential - and his shortcomings. It's right that a captain should advise youngsters in private, but players take offence when criticised in public, especially when the guy mouthing off isn't leading by example.

Against Milan, as for the past two months, Philippe Senderos was head and shoulders above his fellow centre back. Senderos may not be the greatest defender, but he won't shirk or sulk when the going gets tough. I don't feel confident saying the same about Gallas. I played against him in the French league and whenever we were challenging for the ball he gave me withering looks of contempt, as if he was offended by the prospect of a physical contest. I quickly realised that he's the sort of player who can be intimidated.

The mark of a captain is how he performs when there's a crisis, not when the team are basking in glory, and Gallas still has a lot to do to erase the memory of his childish behaviour in the match against Birmingham City, in which Eduardo da Silva broke a leg. He's dished out compliments, now it's time to earn some.