Former Arsenal goalkeeper Jens Lehmann believes new signing Petr Cech will have to get over emotional ties with Chelsea to achieve success with the Gunners.

32-year old Czech Republic international Cech left Stamford Bridge after 11 years to join the Gunners last week and Lehmann feels he quickly has to put his memories with the Blues to the side so he can focus on achieving success in North London.

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."

The German also believes Cech's winning mentality will help the Gunners to mount a serious challenge for their first Premier League title since 2004.

He added: "With someone in there like Petr, with Per Mertesacker now as captain, they can re-establish this winning attitude and mentality."