PSG have taken just one point from their last three matches when the chance was there on each occasion to wrap up the Ligue 1 Conforama title. A 3-2 defeat at FC Nantes on Wednesday was the latest missed opportunity, but they have the chance now to celebrate in front of their own supporters when they face Monaco at the Parc des Princes.
"Before our last three league games, we had a 20-point lead and everyone was saying the league was over, but that wasn't the case," Tuchel said on Saturday.
"Now we have to show that we're able to stop this situation and win the title. It's not the moment to focus on Lille's result, but focus on ourselves. I expect a reaction from us against Monaco, a good performance, and that we show an attitude that matches our ambitions."
The Monaco game is also the last rehearsal before next weekend's Coupe de France final against Stade Rennais FC, and Tuchel is hoping to have a host of players back from injury. Neymar is one of them - the Brazilian has not played since late January due to a foot injury.
Neymar 'feels free'
"Ney has taken part in a lot of full training sessions. He's working hard, very hard, with a great attitude and he's looking forward to playing, that's clear," Tuchel said before his squad trained on Saturday.
"The test results are good, he doesn't feel any pain. There are two sessions left before we decide on whether he might feature against Monaco, but I have noted that he feels free, confident, in recent times.
"The most important thing with Ney is that he feels free on the pitch, happy to play without apprehension, and that he's protected by the referee too. I honestly hope that after this injury he'll keep his passion for the game, because he's a special player, everyone comes to the stadium to see him play. He likes challenges, that's his style, and perhaps we'll see him on Sunday. I hope so, in any case."