Rafael Nadal made a triumphant singles return after a seven-month absence, beating Argentinian qualifier Federico Delbonis 6-3, 6-2 in the second round of the ATP clay-court tournament here.

The 11-time Grand Slam champion from Spain hadn't played since a shock second-round exit from Wimbledon in June.

A torn tendon and inflammation in his left knee had kept him out of the London Olympics and the 2012 US Open, while a virus further delayed his return to action this year.

The rust was showing as Nadal, now ranked fifth in the world, dropped his serve in the first game of the match and quickly fell into an 0-2 hole.

But he rebounded in style against his 128th-ranked opponent, regaining the break in the fourth game before prevailing in a hard-fought eighth game to give himself a chance to serve for the opening set.

He raced to a 4-0 lead in the second, seeming to move with ease around the sun-splashed red clay-court - even when racing to the net after drop shots. He locked up the match after 87 minutes and coming up with four aces and facing just one break point.

Former world No 1 Nadal, playing with the familiar band of tape around the bottom of his left knee, had looked keen to get things under way as he danced on the balls of his feet during the coin toss, wearing a bright purple shirt and gray shorts.

He had vocal supporters in the packed grandstand as he made his first appearance in eight years in Latin America's "Golden Swing" of tournaments.

Nadal, who will be 27 in June, had downplayed his expectations for his comeback event. But his world ranking gave him the No 1 seed here and a first-round bye.

"I feel happy to be playing singles again. It's been an important day for me," Nadal said after the match. "Thanks for supporting me. I'd never dreamed of a comeback like this," he said in front of an ecstatic crowd.

"It was a tough start. Federico played really well and forced me to run a lot.

"I'm happy the knee responded well," Nadal said.

In the quarterfinals he'll face either compatriot Albert Montanes or Portugal's Joao Sousa.

Nadal, who has claimed seven of his Grand Slam titles on the clay courts of Roland Garros, is slated to play clay tournaments in Brazil and Mexico before heading up to the United States for the Masters Series events in Indian Wells and Miami on the hardcourts that are more wearing on his knees.

After that beckon Monte Carlo, Barcelona, Rome and on to Paris - the red clay route that Nadal has dominated like no-one else over the past eight years.