ROME (AP) - Rafael Nadal's preparations for the French Open continued apace as he swept past 13th-seeded Jack Sock 6-3, 6-4 Thursday to ease into the Italian Open quarterfinals and extend his winning streak to 17 matches.
The world number two defeated Roberto Bautista Agut 6-4 6-4 to reach the last eight of a tournament he has won four times previously.
Djokovic, beaten in the final by Britain's Andy Murray a year ago, will now face Juan Martin del Potro in the quarters after the unseeded Argentinian's third round 7-6 (7/4), 6-3 win over Japanese seventh seed Kei Nishikori.
"I thought I played pretty well out there", said Isner, who is ranked 24th. "But I ll keep fighting". Isner did not lose his serve at all against Wawrinka, and Isner recorded the only service break of the match in the seventh game of the second set.
Serbian tennis star Novak Djokovic on Monday said he remains as motivated as ever to reclaim his old position at top of the Association of Tennis Professionals (ATP) rankings, although he has not played his best match this year.
"It's coming at the right time, we're getting closer to Roland Garros".
"I played a more aggressive game and I'm serving better".
Murray's best performance was winning the Dubai title in February, but he looks to be struggling to replicate the blistering displays that carried him to the number one spot at the end of a year ago.
Third seed Stan Wawrinka became the latest high-profile casualty at the Italian Open on Thursday when the Swiss was knocked out in the third round by American John Isner. "I was very happy with the performance".
The eighth-seeded Austrian was forced to save three match points before battling to a 3-6 6-3 7-6 (9/7) win over another American, Sam Querrey.
In other matches, there were straight-sets wins for Marin Cilic, Milos Raonic and Alexander Zverev, accounting for David Goffin, Tomas Berdych and Fabio Fognini respectively, the latter proving unable to build on his upset win over Andy Murray.
Australian Daria Gavrilova beat former finalist and 10th seed Madison Keys 2-6, 7-5, 7-5, while Dutch 15th seed Kiki Bertens put out Monica Niculescu of Romania 2-6, 6-2, 6-1.