Kevin Anderson OUT of US Open

Dominic Thiem  stretched 2017 finalist Kevin Anderson far and wide to achieve a pair of firsts at the US Open.

The ninth-seeded Thiem beat Anderson for the first time on hard courts, 7-5, 6-2, 7-6 (2), to make his first Grand Slam quarterfinal outside of Roland-Garros.

Thiem had never passed the fourth round in Flushing, falling three times in the past four years. But the 24-year-old Austrian served nearly perfectly and gave the 6-foot-8-inch South African little time to unleash his mammoth groundstrokes.

“It was one of my best matches ever,” Thiem said.

Anderson won the first six of their head-to-head meetings, all on hard courts. But Thiem won in straight sets, earlier this year, on the quick-moving clay in Madrid.

On Sunday, he played as if they were on a clay court at times and flipped the script against Anderson. Thiem, not Anderson, dominated on serve, winning 91 percent of his first-serve points (41/45) and never facing a break point. His heavy groundstrokes and soft drop shots forced Anderson to retrieve from side-to-side, back-to-front.

Anderson served and volleyed, and he came to net 48 times, trying to take advantage of Thiem's deep return position – he stood nearly next to the line judges and with his back against the Chase sign in Louis Armstrong Stadium.

But the fifth-seeded South African might have been feeling the effects of his earlier matches. He had already spent nearly 10 hours on-court, battling cramps and beating Ryan Harrison in five sets during his opener, and on Friday, playing another three hours, 43 minutes against No. 28 seed Denis Shapovalov.

“For sure, also, this court helped me,” Thiem said. “It's very, very big. I could go far back at the return, which helped me, which is a little bit like on clay, and this was also a little bit of an advantage today.”

Thiem broke in the 11th game of the opener, for the first break of the match and served out the set. Anderson was then broken to love to start the second and Thiem rolled from there. After the second set, the South African went to the locker room for more than eight minutes, and he regrouped to erase a break point in the seventh game and force a tiebreaker. But Thiem, on his first match point, chased down an Anderson volley for a backhand slice winner, his 41st of the day.