Tuchel claimed he gave the German a second chance after his struggles in the Champions League in midweek.
Havertz repaid that faith with the opening goal in Chelsea’s 4-1 against Crystal Palace to put himself in pole position start up front in the quarter-final second leg against Porto on Tuesday.
But Tuchel made it clear he still expects more from the £71million summer signing.
“He has quality, he needs to show it.” said Chelsea’s manager. “It is as easy as that.
“He will never be our emotional leader and we don't expect him to be. But we expect him to show his quality.
“He can be in the half position or high up the pitch, there is not so much a difference for me.
“Honestly, he needed to show he can do better. There are so many decisive matches coming.
“He got a second chance to show up after the Porto game. It was another chance to show he can do better and he did it, even though he could have scored more goals and he can be more ruthless.”
Havertz, himself, admitted he should have been more ruthless.
He told Sky: “I think the most important thing is we won.
“After the 5-2 defeat it was a good game from us. We could've scored more goals but we can be happy.
“In my position, you always want to score but in the last few months, it wasn't easy. I think I could've scored one or two more goals more but we are happy.”