Rafael Nadal and Serena Williams breezed into the Madrid Open third round with their title defences facing little strain, while Andy Murray made a successful return to clay after nearly a year's absence.

Nadal fed his confidence with a 6-1, 6-0 victory over Juan Monaco of Argentina, just what the top-seeded Spaniard needed after coming to the Spanish capital on his worst clay run in a decade.

The Spaniard failed to advance past the quarterfinals of his last two clay tournaments.

But after Monaco broke to get to within 2-1, Nadal did not relent as he didn't drop another game at Manolo Santana centre court.

"I was dominating over the points and playing very well. I think I've done positive things," Nadal said.

Nadal's hopes of winning a second clay event after his triumph in Rio de Janeiro this year were bolstered when Australian Open champion Stanislas Wawrinka lost and Roger Federer withdrew for the birth of his second set of twins.

Second-ranked Novak Djokovic is absent due to injury.

I'm literally taking it one day, one match at a time, and not putting any pressure on myself.

Serena Williams, World number one

Serena too good

Williams, meanwhile, broke Shuai Peng three times in a 6-2, 6-3 as she dominated her Chinese opponent on serve by firing 11 aces.

The American, who moves on to face Spanish player Carla Suarez Navarro, looked fresh and focused while dismissing any injury fears despite a heavily wrapped left leg.

"I just had some issues and went preventive to make sure I didn't make anything worse," said Williams. "I'm literally taking it one day, one match at a time, and not putting any pressure on myself."

Andy Murray is due to meet Nadal in the semifinals after the Scot overcame Nicolas Almagro in a 6-1, 1-6, 6-4 victory.

Elsewhere, Tomas Berdych beat Kevin Anderson, Jo-Wilfried Tsonga was beaten 6-4, 6-3 by Colombian player Santiago Giraldo, while while Roberta Vinci of Italy knocked out Caroline Wozniacki 6-3, 6-3.

Source: AP