George Graham has heaped praise on Chelsea but admits that next season will provide a stern test for Jose Mourinho's side.

The Blues drew 0-0 at Graham's former club Arsenal on Sunday which kept them 10 points clear of the Gunners with five fixtures remaining.

Graham suggested that after winning this season's Premiership, Chelsea will have their work cut out for them in trying to defend the title next term as well as improving in the Champions League.

'The difficulty for Chelsea next season will be the demands for the team to be more expansive and the challenge of improving their performance in Europe,' he wrote in his column for the Daily Mail.

'Mourinho will need a bigger squad, particularly in key positions through the spine of the team. Then the challenge is to keep them happy.

'They are a difficult team to beat, deliberately so because Mourinho wanted to win the League this season. He is an impressive manager.

'As for them being boring to watch, I would be delighted to be in charge of a team that had only been beaten twice in the league all season. They will be champions and deservedly so.'