Uefa Champions League: Theo Walcott is the perfect successor to Perry Groves, according to the man himself. The former Arsenal flyer readily admits that the 17-year-old winger is in a different class from how he played but there is one key similarity between them.

Groves was very pacy winger for the Gunners for six seasons from 20 years ago. His speed was usually brought to bear as a second-half substitute when opponents were tiring and, for the moment at least, that is how he advocates using London N5's most promising prospect.

The Arsenal fans' clamour for Walcott to come on was vindicated when he turned round the team's fortunes with two assists in the 3-1 win over Hamburg on Tuesday night. But, Groves insists, that should not be transformed into a campaign for the youngster to be used from the start. "Because he is such a talent for a young lad, we all want to see him on for the whole 90 minutes," he said. "But because of the size of the Emirates pitch, the way Arsene is using him at the moment is absolutely right.

"Theo's on top form so when he comes on he is giving the crowd a lift. They go berserk. That makes him feel fantastic and makes the whole team feel fantastic. Personally I would have had him on from half-time but you could see the time was coming when there was half an hour left of the game. Hamburg were breathing out of their arses and the last thing they needed to see was someone who can catch pigeons coming on.

"I could do that, but he's got a great touch with it. I was probably quicker than him - I reckon I would have beaten him in a foot race - but the ball was my problem." That comment reflects Groves' light-hearted view of his own legacy to the game. And he is excited about what Walcott will achieve for his club. "There's no better place for his development than at Arsenal with Wenger and Thierry Henry," he added.

Walcott's influence has helped Arsenal to top spot in Champions League Group G with one game remaining, a position they share with Porto, the team they beat 2-0 at the Emirates and whom they play in their final, decisive game. A draw in that match will take Arsenal through as group winners irrespective of CSKA Moscow's result against Hamburg.

If Arsenal lose while the Russians take three points in Germany, however, it will send last season's Champions League finalists out of the tournament and into the consolation competition of the Uefa Cup. And for their progression to the knockout phase to be comfortable, Arsenal need to get out of the habit of going behind early. It was Freddie Ljungberg who made way for Walcott on Tuesday night and, though he does not believe Arsenal's victory against the Germans was unmerited, it followed a worrying pattern of recent matches.

"Conceding early goals does make it more difficult for us and puts a bit of pressure on us," the Swede admitted. "When we came out in the second half and went behind them, we created more chances. In the end, I think we deserved to win the game."

Walcott's opportunities to force his way into the first-choice XI may be limited with the Swede's return. Ljungberg had been out for six weeks with first a calf problem and then suffering migraines because of an allergy to cheese while away with Sweden on international duty. "It felt really good to play again, although after six or seven weeks out, I did feel a bit tired in the end," he said.