From The Telegraph....
It was, as Phil Foden said afterwards, a “strange” game, with neither attack having to hit the heights to unpick some curious defending and bizarre decision-making, even if Mahrez’s goals and contribution for the third were dazzling. But there was nothing stranger than the failure to award Foden a penalty shortly after the half-hour mark when Alex McCarthy, the Southampton goalkeeper, swiped away the City midfielder’s standing leg.
Graeme Souness and Chris Waddle said Foden had been “too honest” by just about staying on his feet, and there is little doubt he should have gone down. But it becomes difficult to turn around and blame players for diving or tumbling theatrically when they run the risk of honesty getting them nowhere. It was hard to understand how referee Jonathan Moss had missed it but even more bewildering was the video assistant referee Andrew Madley’s failure to overturn the decision.
The official explanation was that, because Moss felt McCarthy had got a touch of the ball and Madley could not determine that was not the case, the decision stood. Foden said he would continue to act honestly but you would not blame him if he thinks twice about staying on his feet the next time he is in this position. “I’m an honest guy and I never like to dive, I always like to stay on my feet but 100 per cent I thought it was a penalty,” he said.
Guardiola was in disbelief. "It is just incredible that penalty was not given,” he said. “One day they are going to explain why. I do not understand it. It's incredible that in four-and-a-half-years we have won everything ourselves. No-one has given us anything.”