Novak Djokovic laid down the challenge to his French Open rivals by only dropping five games in a first-round win against Sweden's Mikael Ymer.

The Serb top seed, who is bidding for an 18th Grand Slam and a second French Open, eased to a 6-0 6-2 6-3 victory.

After cruising to a 20-minute opening set, Djokovic ruthlessly maintained his level to win in an hour and 38 minutes.

"This is what my intentions will be, trying to get off the blocks very strong with a good intensity," he said.

"Obviously these conditions are different than what we are used to here in the French Open. Everyone has been talking about it. The balls, the heavy clay, the cold weather.

"It all affects the play, of course. But I think it's quite suitable to my style of the game."

Ricardas Berankis will be Djokovic's next opponent in Paris after the Lithuanian world number 66 beat Bolivia's Hugo Dellien 6-1 6-4 6-4 to tee up the opportunity to become the first player to beat the Serb on the court this year.

The world number one's only defeat in 2020 came when he was defaulted from his US Open last-16 match against Spain's Pablo Carreno Busta after hitting a line judge with a ball.

Djokovic is one of the clear favourites - alongside Spain's 12-time champion Rafael Nadal and Austria's two-time runner-up Dominic Thiem - to win the men's singles at the delayed clay-court Grand Slam.

This was Djokovic's first appearance at a Grand Slam since his undignified exit at Flushing Meadows three weeks ago.

The Serb bounced back by winning the Italian Open on the Rome clay last week and has vowed not to let the Flushing Meadows incident have "any significant negative impact" on his performance.

That proved ominous for 22-year-old Ymer, who could not cope with Djokovic's intensity and precision on Court Philippe Chatrier.

"I actually enjoyed myself on the court. I think I played really well. A few hiccups here and there, but I think generally the game is there," said 33-year-old Djokovic.

"I'm ready physically, mentally, emotionally to go deep in the tournament."

Tsitsipas & Rublev fight back - just two days after Hamburg final

Fifth seed Stefanos Tsitsipas recovered from two sets down to beat Spain’s Jaume Munar 4-6 2-6 6-1 6-4 6-4 and move into the second round.

Munar, 23, is ranked 109th in the world and was aiming to win only his second senior match at Roland Garros.

But Tsitsipas, who won the ATP Finals last year, fought back by dominating the third set and breaking Munar’s serve in the ninth game of the fourth set.

The decisive moment came when the 22-year-old broke Munar’s serve in the seventh game of the final set.

It was the Greek's first career win from two sets down and came just two days after he lost the Hamburg Open final to Russia's Andrey Rublev - who also produced a brilliant comeback from a two-set deficit.

Rublev, the 13th seed, lost the opening two sets on the tie-break before beating American Sam Querrey 6-7 (5-7) 6-7 (4-7) 7-5 6-4 6-3 for his first main-draw win at Roland Garros.

Tsitsipas will now play Uruguay’s Pablo Cuevas after he beat Swiss qualifier Henri Laaksonen 6-1 2-6 6-4 6-2.

'I will leave the bubble as soon as I can' - Pospisil

Italian seventh seed Matteo Berrettini claimed an equally straightforward victory, beating Vasek Pospisil 6-3 6-1 6-3.

The Canadian will continue in the doubles tournament but suggested he would be glad to leave Paris soon, criticising the bubble players are in because of coronavirus restrictions.

"As soon as I'm done with doubles, I will leave the bubble because it's not a very good bubble here they made for us," said Pospisil, who along with Djokovic is one of the driving forces behind the Professional Tennis Players Association, a proposed new men's players' union.

"It's not easy mentally to be in it. As soon as I have an opportunity to leave the bubble, I will."

There was better news for another Canadian, ninth seed Denis Shapovalov, who hit 55 winners and broke serve 11 times in a 6-2 7-5 5-7 6-3 win over France's Gilles Simon.

Spain's Roberto Bautista Agut, seeded 10th, knocked out another home player in the shape of Richard Gasquet, winning 7-6 (7-5) 6-2 6-1.