Diarra made his name at Real Madrid.
"It's true I've played with some great, great, great players in my career," the Malian admitted to fulhamfc.com. "But also here at Fulham we have great players.
"It was easy to play with the people I did at Real Madrid. Fortunately I played a lot of times with David Beckham and believe me, he works very hard. I have learnt a lot from a lot of great players; people like Roberto Carlos, van Nistelrooy, Raul, Ronaldo. They were unbelievable."