'What happened, happened': Novak Djokovic
'What happened, happened': Novak Djokovic AFP

Novak Djokovic begins the defense of his French Open title at a rainswept Roland Garros on Tuesday, confident his Grand Slam pedigree will help overcome his lackluster season.

The world number one, seeking a fourth Roland Garros title and record-extending 25th major, is enduring his worst run since 2018.

Djokovic, 37, has not won a title in 2024 and has yet to make a final with semi-final spots at the Australian Open and Monte Carlo Masters his best performances.

He also suffered the indignity of being accidentally hit on the head by a metal water bottle in Rome which caused nausea and dizziness.

In Geneva last week, where he was knocked out by Tomas Machac of the Czech Republic, Djokovic said he had been suffering from a stomach problem.

"They are rather bumps on the road," said Djokovic, who watched his long-time rival and 14-time champion Rafael Nadal bow out of the tournament against Alexander Zverev on Monday.

"I have always looked ahead, what is the next challenge, and what it takes for me to be better than I was last week."

When asked to elaborate on his difficulties so far this season, Djokovic opted for discretion.

"Various things have been happening in the last couple of months, but I don't want to get into it. I don't want to open Pandora's Box.

"What has happened, happened, and it's in the past. I know exactly what I need to do in a Grand Slam environment. I've experienced that 24 times in my career."

On Tuesday, Djokovic will take on French wildcard Pierre-Hugues Herbert who he defeated in their only other previous meeting at the Paris Masters in 2013.

Herbert, the world number 142, made the third round in 2018 but hasn't won a match on the main tour this year.

There were 40 matches still to complete in the first round when play got underway Tuesday but torrential rain prevented any play on the uncovered outside courts for the first three hours of the program.

Under the roof of Court Philippe Chatrier, Frenchwoman Alize Cornet's career ended with a straight-sets defeat by Zheng Qinwen in her record-extending 69th consecutive Grand Slam appearance.

Cornet was no match for China's Australian Open runner-up Zheng, losing 6-2, 6-1.

She made her debut at Roland Garros as a 15-year-old in 2005 and has not missed a Grand Slam tournament since the 2006 US Open.

Cornet reached a career-high ranking of 11th in 2009 and enjoyed a surprise run to the 2022 Australian Open quarter-finals.

"I already cried yesterday watching Rafa," said a tearful Cornet after seeing Nadal lose what was likely his last match at the French Open on Monday.

On the covered Court Suzanne Lenglen, Elena Rybakina powered into the second round with a 6-2, 6-3 victory over Belgian Greet Minnen.

The former Wimbledon champion will next face either three-time Grand Slam champion Angelique Kerber or Dutchwoman Arantxa Rus.

Kazakh world number four Rybakina is the only player to defeat tournament favourite Iga Swiatek on clay this season, in the Stuttgart semi-finals in April.

Elsewhere on Tuesday, two-time Australian Open champion Aryna Sabalenka gets her bid to reach a first Roland Garros final underway.

The world number two has reached at least the semi-finals in each of the past six Grand Slam events.

Sabalenka is also the only woman to beat world number one and three-time French Open winner Swiatek in a final on clay -- in Madrid last year -- since the Pole lost her first WTA title decider as a teenager in 2019 at a low-key event in Switzerland.

The 26-year-old Sabalenka had never even reached the second week at Roland Garros until last year, when she was knocked out by Karolina Muchova in the semi-finals.

"Iga definitely motivates me a lot to get better, and I think I improve so many things just because of her. She kind of like pointed to the things I wasn't good at," said Sabalenka who starts her Paris campaign against Russia's Erika Andreeva.

Also on court in the men's singles on Tuesday is Argentine qualifier Roman Andres Burruchaga who has sporting success in the blood.

His father Jorge famously scored the winning goal for Diego Maradona's Argentina in the 1986 World Cup final against West Germany.

Ranked at 144, the 22-year-old is making his Grand Slam debut and takes on Germany's Jan-Lennard Struff.

All over:  Zheng Qinwen embraces Alize Cornet after ending the Frenchwoman's career on Tuesday
All over: Zheng Qinwen embraces Alize Cornet after ending the Frenchwoman's career on Tuesday AFP