Rafael Nadal
Rafael Nadal's one and only defeat at Roland Garros came at the fourth round stage in 2009 to Robin Soderling, but it would be a major surprise if Juan Moncao pulled off the same feat on Monday. Reuters

When and where: Day five at Roland Garros gets underway at 5 a.m. ET. A free live stream will be available throughout the day on TennisChannel.com. ESPN3 will also enable online viewing, while ESPN2 will have live coverage until 10 a.m., when the Tennis Channel will take over.

Preview: The two defending champions take to the court for their second-round matches at Roland Garros on Thursday. In the men's Rafael Nadal continues his quest for French Open title number seven as he takes on Uzbekistan's Denis Istomin. The Spaniard came through his opening round with Simone Bolelli for the loss of just five games and is unlikely to be tested much more against the 43-ranked Istomin.

Nadal has won the only two matches the pair have played, both back in 2010.

While Nadal is favorite to retain his title, the same cannot be said of the defending women's champion Li Na. The seventh seed has struggled to replicate the form that took her to her maiden grand slam in the intervening year, but there have been signs of her best returning of late.

Li narrowly missed out on a big title in Rome less than two weeks ago, losing a third-set tiebreak in the final to Maria Sharapova. And that run continued into Roland Garros as Li swept aside Sorana Cirstea in the first-round for the loss of just three games.

Next up is French veteran Stephanie Foretz Gacon, who will be looking to reach the third round of a grand slam for just the second time.

Li's conqueror in Rome, Sharapova, will also be looking to reach round three on Thursday. The second seed looked in determined mood to win the one slam that has so far eluded her as she ran roughshod over her first-round opponent Alexandra Cadantu, 6-0, 6-0. Up against Japan's 84th-ranked Ayumi Morita, it may be a similar story in round two.

Another match to look out for on day five sees the American man with the best chance of a deep run at Roland Garros, John Isner, go up against France's Paul-Henri Mathieu. Currently ranked down at 261 after missing the whole of last year with a knee injury, Mathieu has been as high as No. 12, four years ago. With the partisan home support in Mathieu's corner, Isner will have to be on his guard to prevent an upset.