Hotshot-Tottenham
Edgar Davids
The contact was made long after the ball had passed. If Sakho had got anything of the ball, you could perhaps argue it could have been a penalty, but it's never given. As it happened, it wasn't a penalty. NBCSN had ex referee Chris Foy as a co-commentator, and he also said no penalty.
As long as the ball is still in play, its location is irrelevant in context of there being a foul or otherwise.