Mbappe was reinstated into PSG's first team last week, a day after being omitted for their Ligue 1 season opener against Lorient and reportedly being frozen out of the main squad for weeks amid an ongoing contract stand-off.
The league's top scorer in the last five seasons watched the 0-0 draw with Lorient from the stands alongside new signing and fellow World Cup winner Dembele, who had completed his transfer from Barcelona for 50.4 million euros ($55 million).
"Kylian is in great shape, he has a lot of desire, a very good state of mind. I am very happy to have a world-class player like Kylian," Luis Enrique told reporters ahead of Saturday's game.
Luis Enrique added that Dembele would be ready to play "from the first minute" but also admitted the club need to strengthen their attack.
The club lost Lionel Messi on a free transfer to Inter Miami, while world record signing Neymar joined Saudi club Al-Hilal for about 90 million euros.
"We still need to strengthen it because it is the line where we had the fewest recruits, but we still have work to do on how they complement each other."
On Neymar's departure, he said: "I think it was a favourable decision for everyone. I would like to thank him for the behaviour he has shown since I arrived.
"He is a world-class player and I wish him well for the future."
Luis Enrique also said he had not chosen the team's captain yet, leaving that decision to his squad.
"It's very simple, I don't choose the captain, the players choose. They met this week," he said.
"There are four captains, it's something that is defined by the players, not by the coach, I want him (whoever the players choose) to be their captain, not my captain."
French media reported that defender Marquinhos is set to keep the armband having captained the side in the last three seasons.
