US Open Tennis 2020 Results: Scores, Highlights from Early Monday Results

Serena Williams' 100th win inside Arthur Ashe Stadium placed her in the U.S. Open quarterfinals for the 17th time. 

The 23-time Grand Slam champion survived a challenge from Maria Sakkari, who beat the American at the Western & Southern Open, which was the tune-up event for the U.S. Open.

Sakkari earned a second-set tiebreak victory, but she was unable to muster another set win against the most decorated player remaining in New York.

Williams will face Tsvetana Pironkova in the final eight after the Bulgarian secured a quarterfinal berth following a three-year absence.

On the men's side, Dominic Thiem continued his quest to make his second Grand Slam final of 2020 by cruising through a match with Felix Auger-Aliassime. 

Thiem joined Australian Alex de Minaur, who also won in straight sets, as Monday afternoon's victors in the men's draw. 

Top Men's Results

No. 2 Dominic Thiem def. No. 15 Felix Auger-Aliassime, 7-6 (7-4), 6-1, 6-1

No. 21 Alex de Minaur def. Vasek Pospisil, 7-6 (8-6), 6-3, 6-2

Thiem received some fight from his Canadian opponent in the opening set.

The Austrian player finally put away the No. 15 seed in a tiebreak, which ended on a gutsy challenge on the baseline.

After the No. 2 seed earned the tiebreak victory, he powered past Auger-Aliassime with ease by outscoring him 12-2 in the final two sets. 

Thiem created an overwhelming advantage in all of the major stat categories. He won 74 percent of his first-serve points, 69 percent of points on second serve and 16 of 18 net points. 

Auger-Aliassime only put 60 percent of his first serves in play and created three break points on Thiem's serve over three sets. 

Thiem will play de Minaur in the final eight. The Australian player advanced to his first Grand Slam quarterfinal with a straight-set win over one of the other Canadians in the draw, Vasek Pospisil.

De Minaur also used a first-set tiebreak to create an advantage. He followed that up by losing only five games in the next two sets. 

The 21-year-old only produced two aces, but he was terrific on his first serve. He won 80 percent of the 50 points on his first serve. 

With the wins by Thiem and de Minaur, the six U.S. Open quarterfinalists come from six different countries. If Matteo Berrettini and Daniil Medvedev win as favorites Monday night, they would make it an octet from eight different nations. 

Top Women's Results

No. 3 Serena Williams def. No. 15 Maria Sakkari, 6-3, 6-7 (6-8), 6-3

Tsvetana Pironkova def. Alize Cornet, 6-4, 6-7 (5-7), 6-3

Just like she did at the tune-up tournament, Williams faced a stiff challenge from Sakkari. 

The Greek player rallied back from down a set to win a tightly contested tiebreak in the second set. 

Williams took control in the final set by winning 12 of her 26 receiving points and earning eight points on 14 second serves. 

Williams did not overpower Sakkari for the entire match, as the No. 15 seed had a better first-serve percentage and win percentage on those shots, but the No. 3 seed found a way to finish off the match. 

With the victory, Williams became the first player to hit the century mark in wins inside the marquee court in New York. 

Each of the three quarterfinal matches confirmed in the women's draw has an American. Jennifer Brady and Shelby Rogers advanced Sunday, and Sofia Kenin can make it four in four with a Monday night win. 

Williams will square off with Pironkova, who has been one of the most remarkable stories of the tournament. 

The 2010 Wimbledon semifinalist followed a similar path to victory as Williams by winning the first and third sets and losing a second-set tiebreak to Alize Cornet. 

Pironkova used a pair of breaks, a perfect net-point record and 14 wins on 17 first serves to close out her fourth victory at the USTA Billie Jean King National Tennis Center. 

Follow Joe on Twitter, @JTansey90.

Statistics obtained from USOpen.org.