Being tactically sound maybe ? The thought of just throwing your best players in regardless of any consideration about tactic or current circumstances will win you matches is pretty naive imo. Football is not that simple, if so no club would have to spend millions hiring the best coaches. All they need to would be buying the best players available then throw them in.
So far we've been really good with counter attacking. Not so good with breaking tight defense. Knowing Mourinho we can be pretty sure he would park the bus and counter. If we go all out from the start that basically means we'll play into their plan. What if one of our backline has a brainfart due to lacking match fitness and Kane or Son score a goal? Our game plan is officially screwed and now we're forced to chase the game with them parking the bus and counter. Not very nice scenario imo.
As I've said, imo we should start relatively slow for 20-25 min to get the rhythm back, it's been like 3 months our players haven't played. If we score, great. If not, at least don't concede. And we'll have an idea of how Spurs would do after this long break, as well as ourselves. Then make changes accordingly, we have 5 subs anyway.
We've never played with both Pogba and Bruno. After a 3 months break, a must win match, lot of unknowns, a tough opponent who 99% would sit and counter is probably not the right match to try new stuff I think.