Rafael Nadal was poised to pull the plug on the chance of a highly anticipated Olympic showdown with Novak Djokovic on Saturday after making the second round of the doubles with Spanish compatriot Carlos Alcaraz.

The 38-year-old effectively ruled himself out of the singles tournament as he battles a thigh injury picked up in training at Roland Garros, the scene of 14 of his 22 Grand Slam triumphs.

Nadal is still listed to face Hungary's Marton Fucsovics on Sunday, with Djokovic lying in wait.

The Serbian world number two completed his part of the bargain earlier Saturday with a straight-sets demolition of Australia's Matthew Ebden.

"I don't know what's going to happen, I don't know if I am going to play tomorrow or not," said Nadal, a singles gold medallist in 2008 and doubles champion eight years later in Rio.

"I will talk to my people and make the smartest decision that I can to have the best chance of bringing a medal home, so let's see."

Nadal, whose career has been plagued by injuries, is playing in only his seventh tournament of the year. His singles ranking has plummeted to 161.

On Saturday, Nadal and Alcaraz, playing together for the first time, defeated Argentina's Maximo Gonzalez and Andres Molteni 7-6 (7/4), 6-4 in their doubles opener.

Alcaraz had earlier enjoyed a winning start to his Olympic Games career when he swept aside Lebanon's Hady Habib, the world number 275, in just 70 minutes winning 6-3, 6-1.

"It was an incredible experience, the energy of the crowd was crazy," said third-ranked Alcaraz, who won the French Open on the same court last month.

Djokovic, chasing a first Olympic gold to add to his 24 Grand Slams, brushed aside Australia's Matthew Ebden 6-0, 6-1 in just 53 minutes under the roof of Court Philippe Chatrier.

Djokovic said he had been looking forward to the prospect of facing Nadal again.

- 'Last time' -

"If we face each other, it's possibly going to be for the last time on the big stage," said the Serb.

Djokovic was barely pushed by 36-year-old Ebden, who only made the tournament as an alternate after a series of injury pullouts.

The Australian Open doubles champion was broken six times and hit just seven winners to the 24 of Djokovic.

Only 10 matches were completed on Saturday as torrential rain washed away any hope of play on the outside courts.

Fourth-seeded Daniil Medvedev, the Russian former world number one playing as a neutral, defeated Rinky Hijikata in straight sets under the roof of Court Suzanne Lenglen.

Women's world number one Iga Swiatek battled to a 6-2, 7-5 victory over Irina-Camelia Begu as the 23-year-old Pole returned to the court where she captured a fourth French Open title last month.

"I'm happy to get through. The atmosphere was a little bit different so I was a little more nervous," said Swiatek, who only made the second round on her Olympics debut in Tokyo three years ago.

Italy's Jasmine Paolini, easily defeated by Swiatek in the French Open final, also made the second round with a 7-5, 6-3 win over Romania's Ana Bogdan.

Saturday's night session closed with Angelique Kerber defeating fellow mother Naomi Osaka, a four-time major winner, 7-5, 6-3.

Former world number one Kerber, 36, and a three-time Grand Slam title winner, will retire from tennis at the Games.

"The last dance is not quite over," said the German.