Arsene Wenger believes people have been 'harsh' in their judgement of Per Mertesacker and is confident the Arsenal defender is getting stronger.
Mertesacker joined the Gunners from Werder Bremen before the close of the transfer window and is still acclimatising to the demands of the Premier League.
Despite his sizeable frame, the Germany international has occasionally struggled and was at fault for Steve Morison's goal in Arsenal's 2-1 win at Norwich City on Saturday.
He was also caught out of position for a couple of the goals in the recent 5-3 victory at Chelsea, but Arsenal manager Wenger maintains Mertesacker brings with him a "commanding influence" at the heart of the defence.
"I feel people have been harsh in their judgement," said Wenger.
"I like Per very much, because he is a very intelligent boy and reads the game very well, has a calming influence, a commanding influence.
"Because he is so tall, sometimes in one situation if he looks a bit not so good, people make a definite negative judgement.
"He grows stronger in every game and we watched him again in Germany against Holland, and he had an outstanding performance. I am really happy with him."
Arsenal face Borussia Dortmund in the UEFA Champions League on Wednesday night knowing victory will guarantee qualification for the knockout stages.
However, despite Dortmund having lost both of their away European ties so far, Wenger is not taking anything for granted.
"We have a good opportunity to qualify against Dortmund, but it will be a tough match because Dortmund are a very good side," said Wenger, his team having drawn 1-1 in Germany in September.
"Also they play as well for their last chance to qualify."