PARIS — Kylian Mbappe struck his league-leading 21st goal of the season as defending champion Paris Saint-Germain won 4-1 at Strasbourg to stay three points behind leader Lille on Saturday.

Coach Mauricio Pochettino defended his decision to play Mbappe for 88 minutes even though PSG has a big game coming up against Bayern Munich in the Champions League on Tuesday.

“The best preparation for him is to be playing. He's a very intelligent lad, very mature in the way he thinks about what he does," Pochettino said. “Our medical staff gives us a lot of information, which allows us to analyze the form of the players. We didn't take any risks with him, nor with any other player.”

The jet-heeled forward put PSG ahead in the 15th minute.

Mbappe latched onto a pass, cut inside a defender and slotted the ball through the legs of goalkeeper Matz Sels, who could have done better.

Moments earlier, Strasbourg midfielder Adrien Thomasson hit the post with a fine shot from just outside the penalty area, with goalkeeper Keylor Navas well beaten.

PSG took control after Mbappe's goal.

Sels was beaten again in the 26th when winger Pablo Sarabia beat a defender on the edge of the area and drilled a low shot into the bottom corner, and Mbappe set up striker Moise Kean just before the break.

Pochettino replaced Navas at halftime with Sergio Rico as a precautionary measure, ahead of the quarterfinal return leg against Bayern with PSG leading 3-2.

Rico was well beaten by 19-year-old striker Moise Sahi's first league goal as he clipped an excellent half-volley into the top corner from a cross in the 62nd.

Pochettino took the risk of keeping Mbappe on, even though the match already looked won after Leandro Paredes hit a fine free kick 10 minutes earlier for 4-1.

“Kylian is the first person who wants to play. He's a World Cup winner, one of the best French players in the Champions League, a forward of great class,” Pochettino said. “I like his mentality, he wants to play in every competition and it shows his level of investment in the team. He's an excellent player, but also a very endearing one who has great humility."

In the other match Saturday, seventh-place Montpellier scored right at the start, just after halftime, and with seconds left in a 3-3 draw against sixth-place Marseille.

Marseille coach Jorge Sampaoli was denied a fourth win in five games since taking charge when striker Gaetan Laborde scored for the hosts with a diving header in the fourth and final minute of injury time.

Marseille fell behind after just 28 seconds when striker Andy Delort latched onto midfielder Jordan Ferri's pass over the top and expertly lobbed goalkeeper Steve Mandanda.

Poland striker Arkadiusz Milik equalized in the 42nd minute when he collected a quick pass from Boubacar Kamara, shrugged off one defender, poked the ball through another's legs and neatly swept the ball inside the post.

Marseille went ahead on the verge of halftime when Dimitri Payet picked out Florian Thauvin near the penalty spot. His effort was blocked by 43-year-old Brazilian defender Vitorino Hilton but the loose ball rolled to midfielder Pape Gueye and he finished confidently.

Ferri again played a long ball behind Marseille's defence in the 46th, and Laborde took it down expertly before slotting through Mandanda's legs for 2-2.

It got worse for Marseille when central defender Duje Caleta-Car was shown a red card in the 62nd, yet Marseille took the lead when substitute Lucas Perrin headed in Payet's cross in the 70th.

Laborde had the last word.

Monaco and Lyon play their games on Sunday, with third-place Monaco hosting last-place Dijon, and fourth-place Lyon facing midtable Angers.

Coach Niko Kovac’s Monaco side is in fine form, having lost just once in the last 19 games.

Lille's defence held firm Friday in a 2-0 win at Metz.

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