Italian Open: Rafael Nadal Thumps Jack Sock to Enter Quarters

Rome: Rafael Nadal, enjoying his best season on clay in two years, booked a quarter-final clash against Austria's Dominic Thiem, whom he beat in the Madrid Masters final last week, after an "aggressive" 6-3, 6-4 win over American Jack Sock, seeded 13th.

The Spaniard, a seven-time champion in Rome and now on a 17-match claycourt winning streak, also swept Djokovic aside in the semis in Madrid.

Another player looking to up his game for the French Open is 2015 champion Stan Wawrinka but the world number three said a lack of confidence was to blame for his shock 7-6 (7/1), 6-4 defeat to big-serving American John Isner, who is ranked 24th in the world.

"When you lack confidence and rhythm, against opponents like (Benoit) Paire and Isner, it's not ideal," said Wawrinka, who had beaten Frenchman Paire 6-3, 6-4 on Wednesday.

"I had some chances to break him at the start of the match, but I didn't push him hard enough.

"My game and my physical condition are there. But confidence, you can lose it quickly. But I'll keep fighting."

Isner, meeting Wawrinka for the first time in six years, will now meet Marin Cilic after the sixth seed from Croatia beat Belgian David Goffin, the ninth seed, 6-3, 6-4.

In the women's tournament, Venus Williams overcame determined Briton Johanna Konta to win their third-round clash 6-1, 3-6, 6-1.

In the absence of sister and defending champion Serena, she will now meet Spain's Garbine Muguruza on Friday for a place in the semis and a possible match-up with Czech second seed Karolina Pliskova.

Williams, competing in Rome because "I still have a lot to give", was more circumspect about her chances of emulating Serena by winning Roland Garros.

"It's so different when you're talking about it or when you're playing it," she said.

"When you're playing it, it's a lot of work. There is not even one point that is given."

Russia's Svetlana Kuznetsova, the seventh seed, suffered a 2-6, 7-5, 6-4 defeat to Australian qualifier Daria Gavrilova.

Gavrilova will meet Dutch 15th seed Kiki Bertens after she beat unseeded Russian Ekaterina Makarova 7-6 (7/3), 6-1.