Bayern boss believes in 'Kane effect' before season opener
Kane signed with Bayern last Saturday and Tuchel said the "fantastic" England captain "has had an immediate impact on the training pitch."
"The way he works and the way he is in the locker room, the way he goes about things, how humble he is and how keen he is.
"He's the first on the training pitch, he works with the reserve players, he's the one who's looking ahead and inspiring others - and that's why he's a big star.
"That's the Harry Kane effect and that's why he raises our chances to win tomorrow massively."
The former Chelsea manager confirmed Kane "would start the game" in Bremen on Friday "if nothing extraordinary happens."
Normally dominant domestically, Bayern have struggled since Tuchel took over as manager in March.
Bayern limped to the Bundesliga title on goal difference after then leaders Borussia Dortmund collapsed on the final day. The Bavarians were eliminated from both the German Cup and the Champions League in Tuchel's first month in charge.
On Saturday, Bayern were thrashed 3-0 by RB Leipzig in the Supercup, where Kane made his debut off the bench.
Tuchel said he was "not worried about Harry" fitting in despite "changing clubs for the first time in his career".
"Of course we're impatient... but Harry is a guy who adapts very fast, around him players will adapt fast."
"We managed to sign the captain of Tottenham and the skipper of the England team so that's kind of what you expect but it's still impressive when you get it."
Tuchel also confirmed injured captain Manuel Neuer would be "back in team practice in a couple of weeks". The manager clarified that the goalkeeper's progress was the reason Bayern did not sign another goalkeeper after letting Yann Sommer move to Inter Milan.
Neuer broke his leg while skiing in December, missing the remainder of Bayern's season.
"What I saw was really impressive" Tuchel explained, "and that changed our plans."
"The priority in all our plans was that Manu would be given time to get back to full fitness."
Bayern CEO Jan-Christian Dreesen on Sunday confirmed the club was "very close" to signing goalkeeper Kepa Arrizabalaga from Chelsea until the Spanish goalie opted to move to Real Madrid.