Ruud van Nistelrooy has told Dimitar Berbatov he would be "crazy to leave" Manchester United, following what has been a disappointing second season for the Bulgarian at Old Trafford.

Van Nistelrooy, who spent five years at United before leaving in 2006, said: "I don't think he should leave yet – this is his second year so I think that he should give it another year at least – I wouldn't leave United that easy. I know what it's like when you've left – it's gone it doesn't come back anymore.

"I was lucky. I was lucky to play with Real Madrid [after United]. Where can you go after United? Probably that's Madrid. But any other thing isn't the same. Now I know what it is – playing for those kind of clubs that's a one-off for a player."

Van Nistelrooy added he could empathise with Berbatov. "Of course I can. For £30m there were big expectations, they aren't complete so far and he isn't regularly playing – OK he plays but not always. Of course that's a disappointment because expectations are sky high but I think that when he has the support of the manager and the lads that he should just carry on and turn it around."