Tottenham vs Antwerp highlights: Giovani Lo Celso and Carlos Vinicius score as Spurs win Group J
Mourinho is giving the back three a whirl today, to not only see it as an option with Reguilon and Doherty for the weeks and months ahead, but also to shore up the same defensive players who were shaky together last week in Austria.
The problem with a back three is that it limits the opportunities for Dele Alli as he's not likely to play out in one of the wide roles which means he's in opposition then with Lo Celso or Ndombele for a central role.
Lo Celso gets the nod as he needs the minutes to play more of a role in the Premier League. Alli will come off the bench pretty sharpish if the result is heading Spurs' way or even if it isn't.
He just needs to shine in any opportunity given, which of course isn't as easy as it sounds.
The same goes for Harry Winks who is finding Premier League minutes hard to come by.
Mourinho has pretty much developed two starting XIs, barring the odd crossover, for the Premier League and Europa League.
It's up to those in the latter line-up to show that they deserve to break into the former, which is no mean feat when it's a table-topping one.
Nobody is exempt from that, including Gareth Bale, and it will fascinating to see how much of a shift the Welshman puts in tonight against the Belgian outfit.
Things are going well at Spurs and competition is fiercer than ever. That's a good thing for the club but it's also tough for Mourinho to manage so many different players with different expectations and morale levels.
Tonight is the kind of night when they need to step up, send a message to the head coach and not prove why he's right, particularly against the team many of them came up short against in Belgium.