Thomas Tuchel says Paris Saint-Germain need Neymar and Kylian Mbappe to be on top of their game if they are to beat RB Leipzig in Tuesday's huge Champions League clash.

Last season's finalists trail Group H pacesetters Manchester United and Leipzig by three points at the midway stage after losing to both teams in their opening three matches, either side of beating Istanbul Basaksehir.

PSG will be facing the prospect of making an early exit from the competition if they lose at home to the Bundesliga club and under-fire head coach Tuchel is willing to risk the fitness of Neymar for a match he has described as a "final".

Neymar missed three PSG games with a groin injury and was released from Brazil duty before being given 30 minutes from the bench in Friday's 3-2 loss to Monaco - a result that increased the pressure on Tuchel.

The forward, who has two goals in seven appearances this term, will start against Leipzig at the Parc des Princes in a repeat of last season's semi-final.

"We need him. He needs to be on the pitch for us," Tuchel said at a news conference on Monday. "He has the quality and the experience.

"He is not in the best shape physically but he will start tomorrow. He can manage that both physically and mentally, though I hope we don't depend on him."

Mbappe scored PSG's two goals in their defeat to Monaco but is without a Champions League goal in 2020, failing to score in 529 minutes across seven appearances in the competition since netting against Galatasaray last December.

"If Neymar or Kylian don't score, of course it has an impact for us," Tuchel said. "I hope they score tomorrow. We need Kylian's goals. He is doing everything possible to be decisive.

"He played with the France team. Against Monaco, he scored two goals. Now is the time for him, as well as for Ney, to be decisive again."

Tuchel started with Neymar, Mbappe, Angel Di Maria and Moise Kean for the win over Basaksehir and has hinted he may go with a similar attack-minded system against Leipzig.

"It is of course a possibility," he said. "We want to win - it's a final in the group. I absolutely want us to have more courage to score than fear to have problems defensively. 

"It will take courage to score, so it's a possibility. We must find two players in the middle capable of making the effort if we play with a 4-4-2. 

"But it is also possible that we play in 4-3-3. We used it in Leipzig as well as in the knockout stages last season. There are two possibilities, we will wait to see who is available."

However, Tuchel will have to make do without Mauro Icardi, Julian Draxler, Idrissa Gueye, Juan Bernat and Thilo Kehrer, while Ander Herrera and Marco Verratti will be assessed later on Monday.

PSG have lost four of their last six games against German opponents in the Champions League, including each of the last two - 1-0 v Bayern Munich and 2-1 v Leipzig.