With De Bruyne facing a spell of between four and six weeks out with a hamstring strain, Foden took centre stage at the Jonny-Rocks Stadium delivering another vital display to help City overturn a 1-0 deficit.
The 20-year-old struck our crucial equaliser with 10 minutes left - his ninth goal of the season - before efforts from Gabriel Jesus and Ferran Torres secured out fifth round ticket and a trip to Swansea.
“He needs to keep doing what he has being doing in terms of when we are in a bad moment or when we are losing in terms of what he gave to the game.
"Phil is in a great moment and with great confidence. he is clinical in front of goal.
“He can play winger, in the middle or in four or five positions up front. He is playing really well, has the physicality and in the right moment he scored a goal.”
City had to dig deep in the latter stages of the game after Alfie May’s 62nd minute strike had given the hosts the lead and got the Robins dreaming of a major FA Cup shock.
And Guardiola admitted he was worried going into the last 10 minutes and said he was happy to have seen his side overcome a huge test of character and resolve.
“Of course (I was worried). But like the Newport game two years ago, we worked, suffered, tried different systems and were there at the end and our quality was the difference,” the City boss added.
“But a big complement to our opponents and I said that to Michael (Duff). They have a fantastic team who defend so compact and they fight as one.
“We are happy to win this type of games, in this competition – we know what can happen all around the world and in Europe when smaller teams can knock bigger ones out and we knew it.
"I know from my experience when we played Newport two years ago and we won in the last minutes of the second half were tough and against Wigan knocked us out so we know the FA Cup and that’s why it is nice that every team can beat anyone.
“But it is about our response in 90 minutes - at 1-0, I didn’t have any regrets about the way we were playing or behaving.
"And fortunately the talent from the cross from Joao the exceptional finish from Gabriel and Phil – the goals were excellent.
“I was very happy with the reaction of the players.”