Guardiola said it was ‘incredible’ not to give a penalty after Foden was brought down inside the area during the first half of the game.
The Citizens returned to winning ways against Ralph Hasenhuttl’s men courtesy of two goals from Riyad Mahrez, two from Kevin De Bruyne and Ilkay Gundogan’s first half strike.
Despite the Manchester-based club putting the Saints to the sword with such a huge margin, Guardiola felt his side should have scored one more when goalkeeper Alex McCarthy impeded Foden.
"Jon [Moss, referee] cannot see it, but the VAR is there, they don't whistle the penalty, it's incredible. For a long time, maybe four or five years, never complain about the referees, but this action really is incredible,” Guardiola said after the game.
“The VAR exists for when the referee doesn't see the action, they can make a mistake, that's why they review. But if there is a review and they didn't whistle the penalty for this action, I don't understand. Honestly. The same with Fulham and Arsenal. Maybe one day they will explain rally the rule for all of the managers and players.
He added: "Tough game. They make us suffer the most this season, without the ball. After two shots on target we scored two goals. Second half we were much, much better. Unfortunately, with the 4-1 we concede a goal we could have avoided.