Defending US Open champ Iga Swiatek needs 49 minutes to beat close friend Kaja Juvan

NEW YORK (AP) — Iga Swiatek didn't hold back against close friend Kaja Javan, defeating the Slovenian qualifier 6-0, 6-1, in just 49 minutes Friday to move into the US Open's fourth round.

The top-seeded defending champion from Poland has dropped only nine games so far in the tournament. She's handed her opponents 19 6-0 sets on the WTA tour this year.

"I didn't like the fact I was kind of winning against my best friend," Swiatek told the crowd in Louis Armstrong Stadium afterward. "Playing her is like playing a sister. ... I don't have many friends but she's my best friend."

Swiatek next faces the winner of the match between 20th-seeded Jelena Ostapenko and American Bernarda Pera.

In the first match of the day in Arthur Ashe Stadium, 14th-seeded American Tommy Paul moved into the fourth round at Flushing Meadows for the first time, defeating No. 21 Alejandro Davidovich Fokina of Spain 6-1, 6-0, 3-6, 6-3. Paul served up the last of his 15 aces to close out the match

Earlier, No. 10 Karolina Muchova moved into the women’s fourth round with a 7-6 (0), 6-3 victory over Taylor Townsend.

Muchova, who reached the final of this year’s French Open, equaled her best showing at Flushing Meadows by pushing the serve-and-volleying American off the net and onto the baseline. The 132nd-ranked Townsend won just 23 of 70 baseline points and had 39 unforced errors.

Muchova came into the US Open with a career-high ranking and momentum after reaching the final of this month’s tuneup event in Cincinnati, losing to American Coco Gauff in straight sets.

She next faces Xinyu Wang of China, a 4-6, 6-3, 6-2 winner over Anna Karolina Schmiedlova of Slovakia.

Later matches include No. 6 Gauff against 32nd-seeded Elise Mertens, and a matchup of two players who recently returned to tennis, Caroline Wozniacki and Jennifer Brady.

No. 2 seed Novak Djokovic will be in action at night in Arthur Ashe Stadium against fellow Serbian Laslo Djere, the No. 32 seed. Djokovic is chasing his 24th Grand Slam title and the departures of three high seeds in his half of the draw – No. 4 Holger Rune, No. 5 Casper Ruud and No. 7 Stefanos Tsitsipas – could help clear his path.