2007 and 2009 champion Nadal is hoping that his odd-year title luck will continue, as he plays with no sign of the hamstring injury that led to an early loss six weeks ago at the Australian Open.

The top seed improved to 28-4 at the desert event as he beat number 105 Sweeting, a rerun of a victory for the seed from Melbourne. He next plays Indian Somdev Devarman who beat Belgian Xavier Malisse 6-1, 3-6, 7-6 (7-5).

"Nothing was impressive, but I played solid," Nadal said. "I didn't have any big mistakes. In general, I am happy with the serve, happy with the backhand. The forehand is always is my best shot, and I need to be aggressive to have chances to have a good tournament."

German Philipp Kohlschreiber produced the biggest upset so far, knocking out fourth seed Robin Soderling 7-6 (10-8), 6-4. Kohlschreiber now stands 4-1 in the series with the Swede, who has played the last two Roland Garros finals but was suffering with an existing ankle injury.

"I am happy about my victory," Kohlschreiber said. "(Soderling) was on court, he played. Maybe he didn't have his best day, and so, but still, I am lucky to be through, I think." Soderling's defeat was only his second of the season, on which he now stands a 19-2 with three titles, the most on the ATP.

"I think I lost the match when I decided to go on court, because today I shouldn't have done that," said Soderling. "Sitting here after the match, it feels like I couldn't give my 100 per cent."

The Swede said he hurt his ankle near the end of a Davis Cup rubber a week ago, then was sick in bed with fever for five days. "It gets a little bit worse when I play, but I hope today I didn't make it too much worse. Hopefully it will be fine."

Donald Young, a winner over fifth seed Andy Murray in the second round, was crushed by Spaniard Tommy Robredo 6-0, 6-4. Juan Del Potro won his eighth straight match to improve to 16-4 in 2011 as he beat Alexandr Dolgopolov 7-6 (7-3), 6-3.

The Argentine who won the 2009 US Open has rebounded from an injury-marred 2010 over the last month, surging from 484th to 90th in three weeks and becoming the huge threat he once was after a title in Delray Beach.

On the women's side, top seed Caroline Wozniacki continued her no- drama run through the field, defeating Maria Martinez Sanchez of Spain 6-1, 6-3. The Danish winner had a challenge as she faced one of the rare serve-and-volley players in the game.

"I'm happy to be through, I knew that this was not going to be an easy one," Wozniacki said. "I'm just looking forward to play my fourth round. I'm happy to be there. I really enjoy playing this tournament, and I'm happy to get another match."

Eighth seed Victoria Azarenka put out Pole Ursula Radwanska 7-6 (7-3), 6-3, while Radwanska's sister, ninth-seeded Agnieszwa, defeated Russian Maria Kirilenko 6-0, 2-6, 7-5.

Russia's Alisa Kleybanova upset Italian 13th seed Flavia Pennetta 6-3, 6-4, and 16th seed Maria Sharapova spoiled the 24th birthday of France's Aravane Rezai 6-2, 6-2.