You have to remember that if Mendy and Cancelo come inside then we'd be giving away a ton of space like we did in the first half against Leicester.For that reason I'm surprised that the fullbacks weren't instructed to tuck inside more to prevent the very simple outballs that Spurs had to their front three every team they won the ball back
I don't think tactics lost it, personally. After 20 minutes we were second to every loose ball. Whether that's fitness or motivation I don't know. Our opening 3 league games last season all had the same problems as we had today; good start, weak middle and weaker finish.