And having missed a great chance from Danilo's cross, Foden struck his first goal for the club in the second minute of added time to cap a memorable performance.
Guardiola has already touted Foden for a senior England call-up and the Catalan was fulsome in his praise for the teenager after he opened his account.
"He celebrated like it was his first goal," said Guardiola.
"This guy is so special, a City fan and he loves the club. You see it in his behaviour and every single action. He is already a great, great football player.
"I don't remember [my first goal], I'm sure it was good but it was a long time ago. Phil, hopefully, it will be the first of many. The first goal too, an amazing assist - and the second.
"Manchester City have a player for the next years."
Foden made his case for more regular selection from Guardiola and the 18-year-old was thrilled to score his first goal for the club.
"It's hard to put into words - it hasn't fully sank in - but I've dreamed about it," Foden said.
"Being a City fan, it's very special to me and I'm happy to help the team to win.
"Mostly in the Premier League I was dreaming of it but it's special in any competition. I ran off mad and it's a moment I'll never forget.
"I enjoy assisting as well as scoring and it's good to have both in my game. I'm learning every day from players like Kevin De Bruyne.
"I felt a little bit unfit but a massive 90 minutes. I would've liked it [the goal] to come much earlier but it's come now and it's a great feeling."