NEW YORK (AP) — A quick look at the U.S. Open:

LOOKAHEAD TO WEDNESDAY

John Millman goes from one of tennis' greatest champions to another. Two nights after knocking out 20-time Grand Slam champion Roger Federer in the fourth round to reach his first major quarterfinal, the unseeded Australian faces No. 6 seed Novak Djokovic. Federer is the career leader in major titles for a man, while Djokovic is fourth after winning his 13th at Wimbledon. That came just after he routed Millman 6-2, 6-1 at Queen's Club in their only career meeting. The other men's quarterfinal is a rematch of the 2014 U.S. Open final, when No. 7 seed Marin Cilic faces No. 21 Kei Nishikori. Cilic won that title match four years ago in straight sets, though Nishikori leads their overall series 8-6. On the women's side, 2017 runner-up Madison Keys can return to the semifinals with a victory over No. 30 seed Carla Suarez Navarro, and a first-time Grand Slam semifinalist is assured in the first match, when No. 20 seed Naomi Osaka of Japan faces Lesia Tsurenko of Ukraine.

WEDNESDAY'S FORECAST

Sunny. High of 86 degrees.

TUESDAY'S WEATHER

Sunny. High of 91 degrees.

TUESDAY'S KEY RESULTS

Men's quarterfinals: No. 1 Rafael Nadal beat No. 9 Dominic Thiem 0-6, 6-4, 7-5, 6-7 (4), 7-6 (5); No. 3 Juan Martin del Potro beat No. 11 John Isner 6-7 (5), 6-3, 7-6 (4), 6-2.

Women's quarterfinals: No. 17 Serena Williams beat No. 8 Karolina Pliskova 6-4, 6-3; No. 19 Anastasija Sevastova beat No. 3 Sloane Stephens 6-2, 6-3.

STAT OF THE DAY

60 — Number of Grand Slam tournaments without a U.S. men's singles champion, the longest drought in the country's history.

QUOTE OF THE DAY

"You know, I have never seen Roger sweat, ever. If he's sweating a lot and has to change clothes, then you know it's pretty humid out there." — Isner.

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