Manchester United have been warned they will need to better Chelsea's renowned spending power if they are to land Lyon midfielder Mahamadou Diarra for next season.

Diarra is thought to be a transfer target for Alex Ferguson. But Lyon chairman Jean-Michel Aulas has made it clear that if United are to have a chance of buying the 24-year-old they will have to shell out more than the £24.5million Chelsea paid for the French club's Michael Essien last summer.

The messages were mixed from Aulas yesterday, who committed Lyon to keeping Diarra but then appeared to leave the door open to big-money offers.

"Diarra will still be with us next season. Even if a good deal is possible people must know he will be more expensive than Essien," he said.