PARIS (AP) — Monaco cruised to a 4-1 victory over 10-man Montpellier in the French league on Sunday following a hat trick from Emmanuel Riviere, while Edinson Cavani scored his first goal for Paris Saint-Germain as the French champion drew 1-1 at home to Ajaccio.

Radamel Falcao gave Monaco a deserved lead from the penalty spot in the 18th minute after Lucas Ocampos was fouled by Siaka Tiene.

Montpellier, which drew against defending champion PSG last week, leveled six minutes later when Victor Montano beat Monaco defender Ricardo Carvalho to head in Benjamin Stambouli's cross.

Monaco restored its lead just before halftime when Riviere won the ball off Daniel Congre and chipped the ball over goalkeeper Laurent Pionnier.

Riviere doubled his tally in the 57th, and matters got even worse for Montpellier when Congre was sent off six minutes later following a foul on Yannick Ferreira Carrasco.

Riviere completed his hat trick nine minutes from time, heading into an empty net after Pionnier had parried Ferreira Carrasco's deflected shot.

Despite being one of the three promoted sides, Monaco is widely expected to be the closest challenger to PSG this season after spending heavily in the offseason. It has won both its opening games, while PSG has drawn both.

"It's perfect at the moment," Monaco coach Claudio Ranieri said. "Two games, six points. Today was very difficult, against a team which plays very compact.

"But Monaco played well, I'm happy. It is important to win but also to play well. I'm happy with that. Now I want to see how things continue, it won't be easy."

In Paris, Ajaccio took a shock lead in the ninth minute. Adrian Mutu cut the ball back to Benoit Pedretti, who unleashed a stunning first-time shot into the top right corner.

That was Ajaccio's only shot all match as PSG dominated and had 39 attempts on goal, but it was frustrated by a well-organized defense and outstanding goalkeeping from Guillermo Ochoa.

Thiago Silva headed a corner onto the crossbar in the 81st minute, before Cavani — who was signed from Napoli for 64 million euros ($84 million) — leveled five minutes later.

Silva again hit the crossbar in stoppage time with a powerful strike, but new PSG coach Laurent Blanc is still without a victory.

"It's football ... we deserved to win," Cavani said. "We had so many chances. But we will get better little by little. With a bit of work, we will reach our aims.

"It's my first goal and moreover it was a good one. But that doesn't mean anything really if we don't win at the end. At least it let us believe we could do it."

Elsewhere, newly promoted Nantes lost 2-1 at Lorient.

Nantes took the lead in the 17th minute in somewhat fortunate circumstances, with Olivier Veigneau's cross from 35 meters out ending up in the far corner of the net.

Lorient leveled five minutes from halftime when Maxime Baca sent a ball through to an unmarked Vincent Aboubakar, who calmly slotted it past goalkeeper Remy Riou.

Jeremie Aliadiere scored the winner with a stunning free kick that Riou got a hand to but couldn't prevent going into the top left corner.

Nantes was prevented from scoring a stoppage-time equalizer by Lamine Kone' last-ditch clearance off the line.