Anderson endured a three-hour rain delay and saved a match point before firing his 21st ace to finish off seventh-ranked Thiem 6-3, 6-7 (6/8), 7-6 (9/7) after two hours and 46 minutes and reach the Washington hardcourt quarter-finals. Thiem, in his first hardcourt tuneup for the US Open, fell to 0-6 lifetime against Anderson, all on hardcourts, but managed to swipe a set from his 45th-ranked nemesis for only the second time in his career.
Nishikori, the 2015 Washington winner, beat three-time champion Juan Martin Del Potro 6-4, 7-5, for only his second victory in seven matches against the Argentine 13th seed. It was the second early morning finish in as many matches for Nishikori, who faces US wildcard Tommy Paul next. Paul, who has never faced Nishikori, has ousted seventh seed Lucas Pouille and 11th seed Gilles Muller.
Russia’s Daniil Medvedev upset Bulgarian fourth seed Grigor Dimitrov 6-4, 6-2, to reach a last-match matchup with Germany’s eighth-ranked Alexander Zverev, who beat American Tennys Sandgren 7-5, 7-5 just before 2 am after killing time with a nap and video games. Anderson saved a match point when Thiem netted a backhand to level the last tie-breaker at 6-6, then hit a forehand winner to set up a match point that Thiem erased with a service winner. But Thiem sent a backhand wide on the penultimate point and Anderson blasted an ace wide to reach his fourth Washington quarter-final, matching his best result.
After an early exchange of third-set breaks, Anderson double faulted on a break point to hand Thiem a 4-3 edge. But Thiem was broken in the 10th game while serving for the match. Next up for Anderson is 200th-ranked Indian qualifier Yuki Bhambri, who eliminated Argentina’s 100th-ranked Guido Pella 6-7 (5/7), 6-3, 6-1.
Canadian third seed Milos Raonic, the 2014 Washington champion, defeated Cypriot Marcos Baghdatis 7-6 (9/7), 6-3 to book a quarter-final against US eighth seed Jack Sock, who downed countryman Jared Donaldson 7-6 (8/6), 6-2.
Halep beats the heat, Petkovic bounces Bouchard
In the women’s event, World number two Simona Halep battled through extreme heat to reach the quarter-finals while Canada’s Eugenie Bouchard was ousted by Germany’s Andrea Petkovic. French Open runner-up Halep, the top-seeded woman on the Washington hardcourts, rallied past Colombia’s Mariana Duque-Marino 3-6, 6-4, 6-2 in withering heat she measured at 47 Celsius (116 F) on the court.
World number 102 Petkovic, a former top-10 player and French Open semi-finalist on the comeback trail, ousted 73rd-ranked Bouchard 6-2, 4-6, 6-0. Petkovic advanced to a quarter-final against 17-year-old Canadian Bianca Andreescu, who won her first WTA main draw matches this week, including Thursday’s 6-2, 6-3 triumph over French second seed Kristina Mladenovic. It was the first time in WTA history a player born in the 21st Century had beaten a top-20 player.
Another quarter-final will see German fourth seed Julia Goerges against Romanian sixth seed Monica Niculescu, who eliminated compatriot Patricia Maria Tig 6-4, 7-6 (7/2). Germany’s Sabine Lisicki defeated Belarus’ Aryna Sabalenka 4-6, 6-3, 6-3. Lisicki will face French fifth seed Oceane Dodin in s other quarter-final.