The Blues got past the French champions in the first leg of their UEFA Champions League last-16 first leg after goals from Kai Havertz and Christian Pulisic to put them in the box seat to make the quarter-finals.
Lukaku came under intense criticism after registering only seven touches in Saturday’s 1-0 Premier League win over Crystal Palace and Tuchel opted to demote him to the bench.
The Belgian forward remained on the bench unused with the Blues always in control and Tuchel explained the decision.
“It was not the moment after the match where everybody was focused on the few touches that he had to put him right into the next fire,” Tuchel told reporters.
“It was the moment to take a step back. That was the decision and that’s it. You can clearly see we had a strong win and strong performance.
“It was a tough match and almost every question is about Romelu. The focus is huge. There were nine other players who did not play.
“We should never forget we consider this sport a team sport and the 11 guys who play do everything to commit fully to what we plan and commit fully to their team-mates. Those on the bench have to do the same and this is how it works.”
Elsewhere, new Juventus signing Dusan Vlahovic struck in 32 seconds in his Champions League debut as the Bianconeri managed a 1-1 draw at Villarreal.
Villarreal, who hit the post from Giovani lo Celso in the first half, levelled in the 66th minute when Dani Parejo ghosted into the box unmarked.
The goal from Serbian forward Vlahovic, who joined Juve from Fiorentina in January, was the quickest Champions League debut goal ever.