ROME (AP) - Top-ranked Novak Djokovic overcame a poor first set and a smashed racket to beat Juan Monaco 4-6, 6-2, 6-3 and reach the Italian Open quarterfinals on Thursday.
Also through at Foro Italico were five-time Rome champion Rafael Nadal, Roger Federer, Serena and Venus Williams and French Open champ Li Na. However, top-ranked Victoria Azarenka withdrew with a right shoulder injury.
With the wind whipping the red clay into the air, Djokovic struggled with his serve and backhand in the opening set before settling down and wearing out Monaco.
"It was a very strange match. It was difficult to play with that wind but the conditions were the same for both us, he just handled it better at the start," Djokovic said, switching between Italian and English. "I was playing far too defensively and passively and he was controlling everything. He was the better player for a set and a half."
Djokovic next meets fifth-seeded Jo-Wilfried Tsonga, who cruised past No. 10 Juan Martin del Potro 6-4, 6-1.
Federer also dropped a set in a 6-2, 5-7, 6-1 win over 2001 Rome winner Juan Carlos Ferrero. However, except for a brief lapse that resulted in a costly break at the end of the second set, Federer controlled with expert serving and an array of winners on a cool and crisp evening with little humidity.
Federer hit 11 aces and led 46-12 in winners, closing out the match with a backhand overhead after following his serve to the net.
Federer won his 74th career title at the Madrid Open on Sunday, and improved to 47-3 since last year's U.S. Open final. He's won seven of his last 10 tournaments.
The 16-time Grand Slam winner faces top Italian Andreas Seppi, who outlasted Stanislas Wawrinka 6-7 (1), 7-6 (6), 7-6 (6) - after Wawrinka wasted six match points.
Earlier, Nadal routed Marcel Granollers 6-1, 6-1 and will next meet seventh-seeded Tomas Berdych, who eliminated Nicolas Almagro 7-6 (3), 6-3. Berdych was the runner-up to Federer in Madrid, where Djokovic and Nadal lost in the quarterfinals on the blue clay.
In other action, Richard Gasquet rallied past No. 4 Andy Murray 6-7 (1), 6-3, 6-2; and sixth-seeded David Ferrer beat Gilles Simon 6-0, 7-6 (5).
Murray skipped the Madrid Open with a back injury, and he said after the loss that it was still bothering him.
On the women's side, the Williams sisters advanced easily.
Ninth-seeded Serena rolled past Anabel Medina Garrigues of Spain 6-3, 6-1 to extend her winning streak to 16 matches after winning titles in Charleston, South Carolina, and Madrid. Serena called for the trainer while leading 4-1 in the second set and had her left ankle re-taped. She then easily won the final two games.
"I wanted to loosen the tape and so I called the trainer to re-tape," Serena said. "It was too tight."
With the French Open 10 days away, Serena is ready.
"I feel good and I have had a lot of practice on clay and today I was running so much and I was ready to play and feeling good," she said. "I wasn't tired at all. I feel good."
Serena's quarterfinal opponent will be Italian hope Flavia Pennetta, who routed Petra Cetkovska of the Czech Republic 6-0, 6-1.
Older sister Venus eliminated fifth-seeded Sam Stosur 6-4, 6-3. She will next face defending champion Maria Sharapova, who beat 2008 French Open champ Ana Ivanovic 7-6 (4), 6-3 after saving three set points in the first.
Wimbledon champion Petra Kvitova struggled before advancing with a 6-2, 5-7, 6-2 win over Sorana Cirstea of Romania. Her quarterfinal opponent will be Angelique Kerber, who easily beat fellow German Julia Goerges 6-4, 6-1.
Li eliminated Chanelle Scheepers of South Africa 7-6 (3), 6-2 and will meet Dominika Cibulkova, who advanced at Azarenka's expense.
As for Djokovic, in the first set alone he committed 22 unforced errors - 14 of which were backhands - to Monaco's 16, and got in only 47 percent of his first serves.
When Djokovic missed two consecutive backhands to hand Monaco the first set, he slammed his racket to the clay twice, breaking it on the second attempt, which drew a warning from the chair umpire.
The burst of anger appeared to help, though, as Djokovic virtually eliminated errors from his game. He improved to 6-0 in his career against Monaco.
"It's not the first time and I don't think it will be the last time - I'm a player with a lot of emotion," Djokovic said of breaking his racket. "I hope kids didn't see it. But then it changed the match. ... The momentum swung to my side."
Djokovic won this tournament for the second time last year, as part of his memorable 43-match winning streak.