Jens Lehmann has warned Petr Cech that he has to forget his emotional ties to Chelsea to be a success at Arsenal next season.
The 33-year-old completed a move from Jose Mourinho's side to the Gunners on Monday for a fee in the region of £10m, but Lehmann has claimed it could take a while for the Czech international to settle at the Emirates Stadium.
He told The Sun: "It's not easy to suddenly go from Chelsea, where he has spent almost his whole career winning many trophies, to the other side of the capital with a rival.
"Before you can have it in your heart to win titles again, you have to get rid of the love you had before.
"At Chelsea, for Petr, it was his passion and he showed great commitment. But, as a professional, he needs to get over it and needs to know Arsenal want him to win things again for them. Yet, let me tell you, that is not an easy thing to get over psychologically. It can take a few weeks, even a few months."
Cech made 486 appearances in his 11 years at Chelsea.