Arsene Wenger has admitted to his 'surprise' at how quickly new signing Thomas Vermaelen has settled at Arsenal.
The Belgium international was brought to Emirates Stadium from Ajax for a fee in the region of £10million earlier this summer.
Vermaelen shone during his debut against Everton at the weekend and was again impressive as the Gunners recorded a clean sheet in their UEFA Champions League win at Celtic.
Arsenal were 2-0 victors in the first leg of their Champions League play-off at Parkhead on Tuesday night, and Wenger was delighted with the display of Vermaelen.
The Gunners 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."