Rafael Nadal was pushed to three sets for the second consecutive match and lined up an Italian Open quarterfinal with Andy Murray on Thursday.
The top-ranked Nadal dropped behind a set and a break against Mikhail Youzhny of Russia, then won 11 of the final 12 games to prevail 6-7 (4), 6-2, 6-1 on another windy day at the Foro Italico.
Murray eliminated Jurgen Melzer of Austria 7-6 (1), 6-4 to celebrate his 27th birthday.
In an upset, the seemingly ageless Tommy Haas beat third-seeded Stanislas Wawrinka 5-7, 6-2, 6-3.
On the women's side, Ana Ivanovic beat two-time Rome champion Maria Sharapova 6-1, 6-4.
Perhaps drained from his three-hour win over Gilles Simon that ended near midnight a day earlier, Nadal didn't generate the usual depth with his groundstrokes, and began to take control only when Youzhny started committing more unforced errors.
Nadal consistently ran around his backhand, a shot that also caused him concern in recent losses to David Ferrer and Nicolas Almagro in Monte Carlo and Barcelona, respectively.
A seven-time champion in Rome, Nadal hasn't lost three matches on clay in one season in a decade, but for a while it looked like he was coming close to ending that streak.
Of Nadal's 29 winners, only two of them came with his backhand.
The oldest player in the draw at 36, Haas used his expertise to give Wawrinka trouble with heavy topspin.
Haas last beat a top-10 player more than a year ago in Miami, where he took out then-No. 1 Novak Djokovic.
"These things don't happen too often anymore, so when I take them I'm really proud of them," the German said. He has been winning this week in Rome for the first time since he lost the 2002 final to Andre Agassi.
Wawrinka cited a back injury that occurred in colder conditions during his opening win.
"I couldn't move too well," he said. "It's really nothing serious. It's just painful and I need some rest - maybe a few days."
Wawrinka has made a great start by winning the Australian Open and the Monte Carlo Masters but another early exit in last week's Madrid Open leaves his form in question with the French Open starting in 10 days.
In other matches, eighth-seeded Milos Raonic defeated 11th-seeded Jo-Wilfried Tsonga 7-6 (5), 6-4, and will next face Jeremy Chardy, the Frenchman who eliminated Ivan Dodig of Croatia 6-3, 6-2 a day after putting out Roger Federer.
In other women's matches, second-seeded Li Na defeated Sam Stosur 6-3, 6-1 and will next meet Sara Errani of Italy, who kept the crowd content by beating Czech qualifier Petra Cetkovska 6-4, 7-6 (3).
Also, third-seeded Agnieszka Radwanska eliminated Francesca Schiavone 6-4, 6-1, and will play 2007 and 2008 Rome champion Jelena Jankovic, who got by Flavia Pennetta 6-2, 6-3.
Zhang Shuai of China also reached the quarters, holding off American qualifier Christina McHale 6-2, 4-6, 6-2.
Later, defending champion Serena Williams and Novak Djokovic were in action.