At that pace, it would still cause him to lose his stride and therefore trip himself. Therefore foul.
I was in a bar in Santanyi here on the island with my friend and her student after a lovely evening swim. There's football on the TV, Real Betis v Deportivo La Coruna and nobody watching. Lots of football scarves of different teams around Europe adorned the wall including Nottingham Forest but nothing from Southampton yet.
I agree the incident in the Spurs v Liverpool game was a definite pen and Mane is a very lucky boy.....should be off.