In beating the Spaniard, ranked eight in the world, Ukrainian Dolgopolov moved to within a round of his best placing in the tournament - he made the semi-finals in 2011 and 2014.

Dolgopolov was joined in the quarter-finals by Australia's Bernard Tomic - the fifth seed defeating France's Adrian Mannarino by the same scoreline.

Second seed Kei Nishikori later crashed out 6-4 6-3 at the hands of Sam Querrey, while Grigor Dimitrov defeated Donald Young 6-3 6-4.

Fourth seed Dominic Thiem beat Dmitry Tursunov 6-7 (5/7) 6-3 6-4 and 18-year-old qualifier Taylor Fritz continued his impressive run with a 6-1 6-3 success over Victor Estrella Burgos, a player 17 years his senior.

Robin Haase and Bernard Tomic progressed with straight-sets victories over Adrian Mannarino and Aljaz Bedene respectively, while Illya Marchenko needed three sets to sink qualifier Ryan Harrison.

In the women's competition, third seed Agnieszka Radwanska eased past Monica Niculescu 7-5 6-1 and Anastasia Pavlyuchenkova had few troubles seeing off qualifier Julia Glushko 6-2 6-1.

There were shocks as qualifier Elena Vesnina beat Caroline Wozniacki 7-5 5-7 6-3 and Jelena Ostapenko knocked out fifth seed Petra Kvitova 5-7 6-2 6-1, while Dominika Cibulkova progressed by virtue of a walkover against Victoria Azarenka.

Naomi Osaka, Christina McHale, Sloane Stephens, Mirjana Lucic-Baroni, Garbine Muguruza, Andrea Petkovic, Roberta Vinci, Carla Suarez Navarro, Johanna Larsson, Saisai Zheng and Yanina Wickmayer also reached the third round.