I think you have to look at those three defeats in context.
Chelsea were riding the crest of a wave since Tuchel came in and had built up incredible momentum.
We rotated a lot for the FA Cup game and still only lost 1-0.
In the league game, we were 1-0 up and cruising when Aguero missed a penalty just before half-time. I have absolutely no doubt that we would've won that game had Sergio not attempted an audacious chip on the keeper.
The Champions League final was the hardest one to take but despite the criticisms over team selection, we lost to a solitary goal and were hardly outplayed. Sometimes it's worth remembering that the other team has really good players too and they are just as desperate to win as we are. It's unfortunate but someone has to lose.
It's also worth nothing that we beat Chelsea home and away last season when Tuchel was still there.
Add all that up and I don't think it's fair to say he has Pep's number.
Also, this a two legged tie which has a completely different dynamic to a one-off final.