Muguruza matched her best US Open showing from 2017 by defeating three-time US Open runner-up Azarenka 6-4, 3-6, 6-2 in the only Slam where the Spaniard hasn’t reached the final.
“It’s a Grand Slam where I’ve been struggling,” Muguruza said. “This year it’s working so I want to keep going.”
Muguruza broke at love in the ninth game of the first set and held to grab the lead, then won after two hours and 15 minutes as Azarenka double-faulted.
“Playing the whole year without crowd, this is super amazing. I feel pumped.”
Romanian 12th seed Simona Halep, a two-time Grand Slam champion battling back after an injury layoff, ousted 19th seed Elena Rybakina of Kazakhstan 7-6 (11), 4-6, 6-3 after two hours and 25 minutes.
“Definitely it has been a very tough match,” Halep said. “I knew she was very powerful. I knew I had to be strong. I knew I had to be calm but I didn’t.”
Halep, her right thigh taped after an injury two weeks ago, failed on six set points before Rybakina, who lost four set points herself, double faulted to end a 17-minute tie-breaker and drop the first set after 64 minutes.
Djokovic moves five matches from Slam
Late on Thursday, world No. 1 Novak Djokovic moved five matches from completing the first men’s singles calendar-year Grand Slam in 52 years by advancing to the third round.
The 34-year-old Serbian cruised past 121st-ranked Dutchman Tallon Griekspoor 6-2, 6-3, 6-2 at Arthur Ashe Stadium to book a third-round date with 2014 US Open runner-up Kei Nishikori of Japan.
“I’m as motivated as ever to do well,” Djokovic said. “I’m not the only player that wants to go deep in the tournament and put his hands on the trophy. I’m trying to be my best every day and let’s see what happens.”
Nishikori made himself an obstacle in Djokovic’s path to history by outlasting American Mackenzie McDonald 7-6 (3), 6-3, 6-7 (5), 2-6, 6-3, avenging a loss in last month’s Washington semi-finals.
Djokovic has a 17-2 career record against Nishikori, who last beat the Serbian star in the 2014 US Open semi-finals. Since then, Djokovic has won 16 in a row, most recently in the Tokyo Olympic quarter-finals.
Tokyo Olympic champion Alexander Zverev beat 33rd-ranked Spanish left-hander Albert Ramos-Vinolas 6-1, 6-0, 6-3.
The German fourth seed, last year’s US Open runner-up and a champion two weeks ago at Cincinnati, took only 74 minutes to advance.
“It’s great that I’m through in three sets and just over an hour,” Zverev said. “I will need that energy. I’ll need that power I have for further matches. I’m happy I only lost four games.”
German Oscar Otte, ranked 144th, became the fifth men’s qualifier to reach the third round by defeating 92nd-ranked American Denis Kudla 6-4, 6-4, 6-2.
There haven’t been so many qualifiers so deep at any Slam since six at the 2011 French Open and not at the US Open since five made it in 1984.
Serbia’s Novak Djokovic celebrates his win over the Netherlands’ Tallon Griekspoor (not pictured) on Thursday. (AFP)