Sept. 8 (UPI) -- Elise Mertens needed just 74 minutes to edge American Sofia Kenin in straight sets in the round of 16 at the 2020 U.S. Open in Queens, N.Y.
"I felt pretty focused. I was trying to focus on my game and not her game," Mertens told reporters. "I was just mentally prepared for a battle."
Mertens had seven aces, zero double faults and just seven unforced errors in the win. Kenin did not have an ace and had three double faults and 26 errors.
"I did better at the U.S. Open than I usually do," said Kenin, who hadn't advanced past the third round of the Grand Slam in five previous trips to Queens. "I'm just going to take the positives from here and try to forget this match.
"I cried after and I'm not happy about the match so we'll see."
Mertens also advanced to the quarterfinals at the 2019 U.S. Open before she lost to eventual champion Bianca Andreescu. She lost to Sloane Stephens in the round of 16 in 2018 and lost in the first round in 2017 and 2016. She failed to advance out of qualifiers in 2015.
Azarenka also advanced Monday with a three-set victory over Karolina Muchova. Williams moved on with a three-set win over Maria Sakkari. Pironkova also beat Alize Cornet in three sets Monday in Queens.
Naomi Osaka -- the No. 4 seed -- battles American Shelby Rogers in a quarterfinal on Tuesday at Arthur Ashe Stadium. American Jennifer Brady faces Yulia Putintseva in Monday's other quarterfinal quarrel.
No. 2 Dominic Thiem, No. 3 Daniil Medvedev, No. 10 Andrey Rublev and No. 21 Alex de Minaur were among those who advanced to the quarterfinals in the men's singles circuit Monday in Queens.
No. 5 Alex Zverev battles Borna Coric in the first men's quarterfinal at 1:15 p.m. EDT on Monday. Monday's second quarterfinal features Denis Shapovalov and Pablo Carreno Busta.