Jens Lehmann has urged Petr Cech to sever his emotional ties to Chelsea after moving across London to join rival club Arsenal.
The 33-year-old ended an 11 season spell at Stamford Bridge by joining Arsenal last month as he looks to gain regular first-team football after being usurped by Thibaut Courtois last term.
Former Germany international Lehmann, who played for Arsenal when they won the 2003-04 Premier League title without losing a game, believes that making the switch between major rivals could be troubling for the former Blues shot stopper.
"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," he told The Sun.
"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.
"With someone in there like Petr, with Per Mertesacker now as captain, they can re-establish this winning attitude and mentality."