United and City played out a scoreless draw in the final Manchester derby of the season on Sunday.
With little happening on the pitch, one of the main talking points happened off it, after United fans aimed a vile chat at City star Foden.
Supporters inside the stadium could be heard singing: "Phil Foden, your mum's a sl*g".
Speaking to the press after the game, when asked about the chants, Guardiola didn’t hold back in condemning those who sang it.
"Lack of class," he said. "But it's not United, it's the people, you know? We are so exposed in the screen in world football - managers, owners, and football players especially.
"Honestly, I don't understand the mind of the people involving the mum of Phil, it's a lack of integrity, class, and they should be ashamed..."