Before and after the first-leg win over Lille, questions were directed at Thomas Tuchel.
After the 2-0 victory, where he had left his summer signing as an unused substitute, Tuchel said it was time to take a step back.
Kai Havertz scored the opening goal and added to his growing reputation as a key player for the big moments in the match.
Is Havertz the best option to lead the line at Wembley?
It took just eight minutes for Tuchel to head home from a corner, thanks to his trust in Havertz.
The German forward had two good chances before the break and he had touched the ball 23 times by the end of the first half.
In the first half against Crystal Palace, he had just two touches of the ball, with one of them for the kick-off.
The focus on such numbers was what led Tuchel to not start the former Inter Milan and Manchester United player against Lille.
The manager said that it was not the moment after the match where everyone was focused on his few touches to put him into the next fire.
It was the right time to take a step back.
The focus is huge because we have had a good win and all the questions are about Romelu. We should never forget that we consider this sport a team sport because there are nine other players who did not play.
It allowed some attention to be placed on Havertz and his development into a crucial player for the club, because he was out of the starting XI.
The German is into his second season at the club and his goal scoring record is solid but not great.
He scored four goals in 27 starts in the premier league last season and nine in all competition this season, with two in the league and seven overall.
He is proving that he is a player who can step up when needed.
He scored the only goal of the game as the Blues beat Manchester City to win the European Championship last season, and his past three goals have all been crucial ones.
Joe Cole said that he has that knack of doing it in big games.
Havertz has that spark or that bit of magic that other players don't. The manager will think about cup finals and big games when he thinks of them.
The games that are big and need someone to stand up and take responsibility get bigger and stronger, according to former Manchester United captain Rio Ferdinand. You can see that he is confident.
He is still a young player but he is making a big impact in big games.
Havertz was a number 10 and his purpose was to create goals for others and chip in occasionally.
The 22-year-old says he enjoys playing in a strikers position, despite facing competition from Romelu Lukaku and Timo Werner.
Havertz said it was good for him.
We have a lot of good strikers so it's good to have a change and not make it easy for the opposition. I enjoy every forward position and it worked well today.
Cole thinks Havertz is capable of flourishing in the centre-forward position.
He said he thought he was brilliant.
I think Havertz's best position is number nine. That is a huge problem because that is not good for him.
He reminds me of Roberto Firmino, the player who knits it together. He would be a nightmare to mark.
At the Club World Cup, he scored two goals, but he hasn't scored a league goal in four years. With Christian Pulisic being withdrawn late on against the French champions, Romelu Lukaku now faces a challenge to prove he should be the first choice.
When a top player finds themselves on the bench, they look at themselves, according to Jody Morris.
He has scored a couple of goals recently in the Club World Cup, but it is not working at the moment. The manager may bring him back to the club at the weekend.
It is a good problem to have for the manager, but he will think he has been proven right.