Palmer was back to his best as he scored in the 3-1 win at Stamford Bridge.
Rooney, on Match of the Day, said: "He's been on a fantastic run since he has joined Chelsea, he has been the catalyst for Chelsea since he joined the club. He's gone through little periods where the goals haven't come as much but his performances have still been really good.
"You have these patches and when you are young sometimes it is difficult to understand why you are having them and how to get out of them.
"The best way to get out of them is to keep things simple and what I really like about Cole Palmer is he actually doesn't - he keeps trying to make things happen by trying the difficult passes to have an effect on the game.
"He looks very calm, very cultured and I am sure that goal will really help from now until the end of the season to help Chelsea get a Champions League spot."