Three explosions rocked the Borussia coach on its way to the stadium in Germany last Tuesday, causing the match to be postponed for 24 hours. Monaco then won Wednesday's game 3-2.
It is still unclear who carried out the attack that injured Dortmund defender Marc Bartra.
"We put what happened behind us, we are emotionally stable and completely focused on the match," Tuchel told a news conference at the Louis-II stadium ahead of Wednesday's second leg.
"We know our qualities and we know what we have to do. We've had an outstanding run in the Champions League and we don't want it to end there.
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"In the first leg it was impossible to be at a normal level, in terms of concentration."
(Reporting by Julien Pretot; Editing by Toby Davis)
