Chelsea's win over Tottenham on Thursday could give Thomas Tuchel more problems than solutions.
The victory was a huge one for the Blues - who are aiming for a late push into the top four of the Premier League.
Under Frank Lampard, the situation was beginning to look dire but Tuchel has overseen two wins and a draw in three matches in charge.
It has pushed them up into sixth and four points off a Champions League spot.
And Tuchel can thank Jorginho, who powered a penalty past Hugo Lloris after Eric Dier fouled Timo Werner in the box, with that being the only goal of the game.
It seems the German has struck upon a winning combination with his three-at-the-back system.
However, that leaves some very key players on the sidelines - and Tuchel now has a selection headache over how to involve them.
The first is N'Golo Kante, who came on for Mateo Kovacic in the second-half against Spurs.
Along with Jorginho, the Croatian controlled the midfield battle against Mourinho's men and was a contender for man of the match.
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But the Frenchman looked rusty when he joined the fray, though that can be put down to the fact he had not played since January 3.
However, in Tuchel's midfield, the basis is on control and possession - which are not Kante's best attributes - while a certain £72m man must be concerned about his chances.
Against Spurs, Chelsea fielded Mason Mount and Callum Hudson-Odoi as pressing machines along with Werner up front and it worked fabulously with the two full of bundles of energy.
After spending a club-record amount on Havertz, that dictates that the German should be a key player in whatever system is deployed.
But following a difficult spell, the 21-year-old is still searching for his position in the squad.
Granted, the ex-Bayer Leverkusen star was denied a starting spot against Tottenham after a minor injury in training prior to the match.
However, Tuchel has a task on his hands regarding the highly-rated midfielder.
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