Just five games into the new Premier League season and Chelsea's title challenge already appears to be in tatters.

The Blues were well beaten by Everton on Saturday, leaving Jose Mourinho with a number of pressing issues to deal with.

Aside from an unsatisfactory summer and key players under-performing, we asked The Sun's football writer Martin Lipton about the talk of tensions between Mourinho and main striker Diego Costa on Off The Ball tonight.

"I think there's a frustration at Costa's lack of fitness and lack of goals which goes back to the tail end of last season where he disappeared in terms of his contribution to the team," he said.

"But [Mourinho]'s got no options. He's got to play him there because he doesn't fancy Remy and I don't think Falcao is up to it. So where does he go? The strikers aren't scoring - any of them and Costa has got to score for Chelsea to be anything like they need to be. At the moment he isn't and he seems to be more interested in picking fights than putting the ball in the back of the net."