The Portuguese midfielder has picked up the award in his first Premier League season, since joining the Reds from FC Porto last summer.
"Raul has always had the ability he has shown recently," said manager Kenny Dalglish.
"Maybe he's settled down a little bit and is more comfortable and confident because he is playing well but there's been nothing drastic for any of the players really.
"It is fantastic to see Raul doing so well. He has always been a talented footballer, he's always had what we are seeing now but it's been trying to get it out and it is coming out now and he's scoring goals."