Gunners banking on Flamini

"Just watch him when he plays," said Arsene Wenger. "He never walks anywhere - he is always running."

The Arsenal manager is talking about Mathieu Flamini, the 20-year-old midfielder who has been handed a key role against Rosenborg.

It is a game Arsenal must win to reach the last 16 knock out phase of the Champions League - and guarantee the £10million revenue they will receive from gate receipts and prize money.

Injuries to Edu and Gilberto Silva plus suspensions for Patrick Vieira and Lauren mean Flamini will make his first start in a major game for Arsenal tonight.

Since arriving from Marseille in the summer he has only played a full 90 minutes in the Carling Cup - an adventure that ended last week after the 1-0 quarter-final defeat at Manchester United.

The one consolation for Wenger was that Flamini appeared one of the few Arsenal youngsters not out of his depth. The Frenchman was the most effective player in his team - moving incessantly, full-blooded in the tackle and refusing to be intimidated. "I enjoyed the atmosphere," he said. "It was a bit heated at times on the pitch, but that is English football, isn't it?"

Flamini has the sort of ice-cool temperament that belies his potentially explosive family roots: he was born in Marseille to an Italian father and Corsican mother.

One manager not deterred by the mix was Jose Anigo, who took charge of Marseille last January and guided a club in disarray into the UEFA Cup Final.

One of his first decisions was to draft Flamini into the first-team squad. "He has such a cool temperament and is not fazed by anything," said Anigo. "That is why one of the first things I did was to call him up."

Anigo, who quit the club two weeks ago, was not to be disappointed as Flamini played his part in helping dispose of Liverpool and Newcastle en route to the final, where they lost to Valencia.

"To be so young and to play at Liverpool and at Newcastle was so good for me," said Flamini. "When I played against Steven Gerrard, I could see he was an exceptional player but I didn't feel out of my depth."

He is equally confident he will not be fazed tonight or on Sunday, should he be chosen to to face Chelsea.

"If Mr Wenger does want me in the team, I feel I am ready," said Flamini. "I will not be afraid of the two matches. I am ready for the challenge. I have experience of playing in crucial games, as in the UEFA Cup last season."

Flamini is sure he was right to come to Highbury. "Arsenal is an opportunity you get only once in your career. I have no regrets. I've adapted better than I expected."