He said: "Arsenal's team has reached a level of maturity that ours hasn't. When we played Crystal Palace there was only one player over 25, so we still need time for players to develop and reach a certain level.
"Henry, Bergkamp, Wiltord and Pires have all been together now for three seasons, Patrick Vieira has been there for nearly seven years. Their spine and their leaders have remained the same for a long time.
"Bergkamp struggled to settle at first and even if you are a World Cup quarter-finalist or winner this game is different and you need time, like our players need time.
"You need to adapt. You need character and you have to overcome the physical aspect of the English game. Once you do that, then because you already have the skill you can really deliver.
"Even Emmanuel Petit said he needed six months to adjust and he was a strong, experienced player when he came to Arsenal.
"They have benefited from a lot of continuity over the last few years and they have a good balance. This season they have also been lucky as well, in games against Fulham, us and West Ham they were very lucky."