John Obi Mikel fears Manchester United boss Sir Alex Ferguson's retirement will make it tougher for Chelsea next season.David Moyes will replace the legendary boss at Old Trafford after the Manchester United boss called time on his 27-year reign.

Mikel warned: "It's going to be even harder to win the title next season because everyone at United will want to prove themselves.

"Sir Alex has been their mentor, he has been behind every trophy, but the players will want to show they are good as well without him. I think it's going to be very tough next season."