Manchester United boss Sir Alex Ferguson believes this season could be the greatest test of Arsenal manager Arsene Wenger's ability.

"I see Chelsea and Liverpool as the main threats because they have the experience and they are consistent," he said.

"They are hard to beat. That won't change. But I can't make up my mind about who is the better team. There is not much between them.

"Arsenal have the biggest job to do because they have sold Adebayor and don't seem to have the money the rest have got.

"How Arsene develops his team will be his biggest test.

"The one thing we know about Arsenal is that they will play some of the best football you will see and they will create chances. They could easily re-establish themselves and challenge for the league again."