Evans led 3-6, 7-6 (6), 4-1 when Indian Wells champion Fritz halted the match. He later wrote in a social-media post, "Today I constantly felt like I was going to pass out, my vision was going fuzzy." He added that he wasn't prepared for such conditions because his recent training was curtailed due to a foot injury, but that the foot held up fine on Thursday.

Evans' quarterfinal foe will be Japan's Yoshihito Nishioka, who upset seventh-seeded Karen Khachanov of Russia 7-6 (2), 7-6 (1).

In the only other third-round match that was completed in Washington, Sweden's Mikael Ymer defeated Finland's Emil Ruusuvuori 6-3, 6-7 (3), 6-4.

Wimbledon finalist Nick Kyrgios led fourth-seeded Reilly Opelka of the United States 7-6 (1), 2-1 when their match was halted due to lightning in the area, and fifth-seeded Grigor Dimitrov of Bulgaria took the first set 6-4 against the United States' Sebastian Korda prior to the stoppage.

Abierto de Tenis Mifel

Top-seeded Daniil Medvedev of Russia needed just 80 minutes to cruise past Lithuania's Ricardas Berankis 6-2, 6-2 in the quarterfinals at Los Cabos, Mexico.

Medvedev finished with an 8-1 edge in aces and won 88 percent of his first-serve points. Next up for Medvedev is a meeting with fourth-seeded Miomir Kecmanovic of Serbia, who routed sixth-seeded Brandon Nakashima 6-2, 6-4.

Two matches were scheduled for later Thursday, with second-seeded Felix Auger-Aliassime of Canada facing the United States' Steve Johnson while third-seeded Cameron Norrie of Great Britain opposing Radu Albot of Moldova.