Doku laid on the winner struck by Kevin de Bruyne as City won 1-0.
The Belgium winger said afterwards: "It was a tough game, they played very well. We didn't play our best but three points is three points. Fair play to them though.
"That is where we belong (City move into third place) and want to be. Today we needed to win and we know there are still games to go so we will prepare well for them."
On De Bruyne's goal, Doku said: "There was no doubt in him still being capable of doing those things. He has shown today that he still has that quality. I am happy for him that he scored.
"They are very strong in the midfield and a very physical team, they played very well. I am not surprised they had a six game run of wins but I'm glad we ended it."
"Now we look forward to being in the Champions League and we still have the FA Cup final to look forward to as well."