The accusation came as a surprise to Tuchel.
"In the Champions League, we wouldn't celebrate any draw. We respect every team," said the German.
"We come from a competition in which we are able to lose against the team 19th in the table 5-2 (West Bromwich). So we know how humbly we have to approach every game.
"In the quarter-finals of the Champions League, if you wish for an opponent you will lose yourself in crazy mind games."
Porto defender Pepe has made the claim this week.
Blues midfielder Mateo Kovacic also said: "It's strange to hear that from Pepe because I played with him for three years. I don't know what he means or if he actually said it. But of course not, we didn't celebrate.
"Me? I didn't celebrate because when I played before with Real Madrid I know that in these stages there are no lucky opponents or bad opponents."