Arsene Wenger admits he is surprised at how quickly Thomas Vermaelen has settled in to his Arsenal defence.
The Belgian international, who reportedly cost the Gunners £10m when he was signed from Ajax in the summer, made a scoring debut last Saturday in the 6-1 win over Everton at Goodison Park.
Vermaelen, 23, was again impressive in last night's 2-0 Champions League play-off win over Celtic at Parkhead which puts the Gunners well on the way to the group stages ahead of the second leg at the Emirates.
The Arsenal boss said: ''Yes, I am surprised but we saw that he had the physical strength and mentality to cope and when he was needed he came in.
''I believe he has a good mix of the physical and technical for a centre-back and it is interesting to have a left-footed player because he gives you angles for the pass which are very important for the midfielder.''
Wenger also described defender William Gallas as ''in the best form of his last two years,'' and praised midfielder Alexandre Song.
''In the last two games Song has played extremely well,'' said Wenger. ''He can win the fight, not only with the physical strength but he has that sense, he can nick the ball from the opponent without fouling and that is an interesting quality.''
Indeed, Wenger was generally pleased with all his players in the victory at Parkhead even though admitted that the two goals which should take the Gunners in to the lucrative group stages were lucky.
He said: ''It was a fierce battle. We dominated the game but Celtic were always fighting and counter-attacking and in the end, despite being in control, we scored two lucky goals. But yes, of course, we merited the good fortune.
''I concede that we were lucky with the goals but we had plenty of opportunity in the first 15 minutes of the second half. We needed a very strong Arsenal side to win the game.
''The crowd was up for it and the team was up for it and if it had been an average performance from Arsenal we would not have won the game.
''The atmosphere was better than the Premier League and people were fair. Celtic were organised and even at 2-0 they never gave up.''