Foden received two bookings in the space of six minutes to end what was his second start of the season on a sour note.
"He doesn't need to prove anything to me," the Spaniard stated. "He would not be here with us.
"I was the guy who said to him in the academy come here to play with us. There is nobody who trusts Phil more than me. I'm the boss, I decide [who plays].
"We thought it was a game he would have more opportunities to run, on the counter-attack.
"Phil has these qualities to be box-to-box, at speed. That was the reason why he played, a tactical decision.
"He's a young guy, still a lot to improve. But it is important. Last season in one of the biggest games we had he played against Tottenham, he played so good and today as well.
"Every minute he plays, more experience for him for his future. He played at a high level."