By Iain Rogers
MADRID (Reuters) - Clay maestro Rafa Nadal was in cruise control in the latest phase of his French Open build-up while Robin Soderling, the man who ended the Spaniard's Roland Garros reign, crashed out of the Madrid Open on Wednesday.
Watched by Real Madrid forward Cristiano Ronaldo and former France captain Zinedine Zidane on an unseasonably-chilly Manolo Santana center court, Nadal thrilled the noisy crowd with some fist-pump inducing winners.
The unorthodox Dolgopolov cracked some mighty winners of his own and mixed his game up with a few deft drop shots but never looked like mounting a consistent threat to the Spaniard's dominance of the red dust.
The Ukrainian qualifier, 21, saved one match point on his serve but on Nadal's second his shot clipped the top of the net and flew long to put the 23-year-old through to face American John Isner in the last 16.
"He's very unusual and very difficult to play against and I helped him play well by playing the ball too short," a self-critical Nadal said at a news conference.
"You know that if you lose your serve it will be very difficult to get back into the set.
"I will try my best to play better than today. I was practicing well but I didn't play well but I think tomorrow will be better for sure."
Andy Roddick's preparations for the French Open were also dealt a blow when he was forced to withdraw due to a virus.
The American world number eight suffered bouts of vomiting and sweating this week and said he found it hard to focus on the ball during his first-round men's doubles loss on Tuesday.
"Playing well there isn't out of the question but it's just going to be a little bit tougher."
Third-seeded Briton Andy Murray, who has struggled since finishing runner-up to Federer at the Australian Open in January, brushed aside Argentine qualifier Juan Ignacio Chela 6-3 6-3 to set up a last-16 clash against Victor Hanescu.
Jo-Wilfried Tsonga, the French seventh seed, retired from his match against Guillermo Garcia-Lopez after receiving lengthy treatment on his lower back with the Spaniard having taken the first set 6-2.
Nadal opted not to compete at last month's Barcelona Open, where he had won the previous five years, to make sure he did not suffer a repeat of the knee injuries that dogged him in 2009 after a grueling European clay swing.
If he reaches Sunday's final, Nadal will reclaim the number two ranking from Novak Djokovic, who pulled out of Madrid due to illness.
(Editing by Miles Evans and Pritha Sarkar)