Doku was on the scoresheet for the 2-0 win.
"The goals (we scored) depend on the talent,” said Guardiola. “Of course we have one more man in the middle. Phil in that position is incredible. It’s quite similar the movement he has done to Jeremy with Erling (Haaland) against United.
“Jeremy in that position one on one against central defender over five metres, he is the fastest player and unstoppable. Over longer distances he may suffer a lot, but over short spaces, how fast he is!
“Always I encourage him to go and prove it and he made an incredible finish at the end.”
On Foden's impact, Guardiola enthused: "You cannot imagine how much we missed him - this is the Phil we know when he played close to Haaland and was the best player in the Premier League.
“Last year he could not be there. His sense of danger close to the box. We are so happy, as I know he is happy and has joy - and when his life is fine, the rest is natural and his incredible talent comes along.”
Asked if he’d spoken to Foden to help him find his form again, Guardiola said: “Not put pressure on him. Everyone in our life we need to be loved.
“Some people are sensitive, and he is a guy who needs to feel embraced. With me, with the club. After that he is the player that he is.”