World number one Novak Djokovic moved effortlessly closer to a first French Open crown on Thursday while 2011 women's champion Li Na crashed out at a rain-ravaged Roland Garros.

Four rain stoppages, and then a final call-off, meant that there was only around five hours of play on a frustrating day which left women's champion Maria Sharapova stranded in her second round match.

But top-seeded Djokovic wasted no time in setting up a mouth-watering clash with Bulgaria's Grigor Dimitrov for a last-16 place.

The Serb, bidding to win a first French Open, and become just the eighth man to complete a career Grand Slam, eased past Argentina's world 83 Guido Pella, 6-2, 6-0, 6-2.

Dimitrov, the 26th seed, will be playing in the last 32 of a major for the first time after breezing past French wildcard Lucas Pouille, the world number 324, in straight sets 6-1, 7-6 (7/4), 6-1.

Djokovic lost to Dimitrov in the Madrid Masters second round earlier this month.

"Even though his style of game could be better on the hard court or faster surfaces, he's showing that he can play equally well on clay," said Djokovic.

"Here it's best of five. It's going to be very physical and all the hard work that I put into in preparations for this tournament hopefully will play into my advantage and will pay off on the court."

Chinese star Li went down 5-7, 6-3, 6-2 to brash American Bethanie Mattek-Sands in what was the 31-year-old's earliest defeat at the tournament in seven appearances.

As Mattek-Sands, the world number 67, looked forward to a third round match-up with Argentine qualifier Paula Ormaechea, Li was left surveying the wreckage of a second successive Roland Garros failure.

Twelve months ago, she went out in the last 16 to Kazakhstan's Yaroslava Shvedova, who herself was beaten by Ormaechea on Thursday.

"I know for sure I lost seven games in a row. It was tough conditions, back to the court three times," said Li after her on-off encounter which started shortly after 1100 (0900GMT) but was only completed just after 1700 (1500GMT).

Mattek-Sands had lost to Li in the semi-finals on clay in Stuttgart, but admitted Thursday's win was one of her most satisfying.

"I knew Li wasn't going to give it to me. She's consistent and good in these situations," said the American.

Seven-time champion Rafael Nadal, who is hoping to become the first man to win the same major eight times, had only started warming up against Slovakia's Martin Klizan before rain meant his match was called off for the day.

Sharapova, meanwhile, was 6-4, 4-2 up on Canadian teenager Eugenie Bouchard.

Third seed Victoria Azarenka went through with a 6-4, 6-3 win over Germany's Annika Beck.

Australian Open champion Azarenka, a quarter-finalist in Paris in 2009 and 2011, next faces France's Alize Cornet.

"I felt like I started the match really well, and then after a little break (for rain) I lost my focus there," said Azarenka.

"But I'm glad I could turn it around and step it up in the important moment."

Former finalist Samantha Stosur and three-time semi-finalist Jelena Jankovic also went through.

Ninth-seeded Stosur was a set and 4-1 up on France's Kristina Mladenovic before a first stoppage.

The Australian then took advantage of a 20-minute window on their return to Court Philippe Chatrier to complete a 6-4, 6-3 win.

The 2011 US Open champion will face Serb 18th seed Jankovic for a place in the last 16.

Jankovic, a semi-finalist in 2007, 2008 and 2010, beat Spain's Garbine Muguruza 6-3, 6-0.

China's Zheng Jie also reached the last 32 with a 6-3, 6-1 win over Melanie Oudin of the United States.

But Czech seventh seed Petra Kvitova ended the hopes of another Chinese player, Peng Shuai, winning 6-4, 6-3

She will next face Jamie Hampton of the United States.

New Zealand's Marina Erakovic, the world 92, put out Slovak 16th seed Dominika Cibulkova, 6-2, 2-6, 6-4 to reach the third round for the first time.

She will face America's Sloane Stephens for a place in the last 16.