The two teams meet on Sunday.
Comparing the two 28-year-olds Tuchel said: "There's one big similarity: they score decisive goals. 'They love scoring and they always have scored no matter the competition.
"Apart from this they are very different players, different styles of play.
"And we need to be very focused if Harry Kane plays, on how to defend, where to close him down, when you close the deliveries down.
"Once he has the ball he's one of the most dangerous guys in the world to finish attacks, he's fantastic in conversion.
"And there are some players around him who deliver well, and can also be decisive.
"Let's see if Heung-min Son can play, because he can also be decisive.
"But we have also some guys around Romelu who are able to serve him and deliver good performances.
"In the end it's a team effort, and it will always be like this."