Djokovic puts unbeaten run on line on Day 5

It's a rematch: Djokovic beat Struff 6-3, 6-1 last week at the Western & Southern Open, part of the 17-time Grand Slam champion's 25-0 start to the season. On the women's side, 2018 champion Naomi Osaka plays Marta Kostyuk, while 63rd-ranked Jessica Pegula's debut in the third round of a Grand Slam tournament comes against two-time Wimbledon champion Petra Kvitova.

Top-seeded Novak Djokovic puts his undefeated record in 2020 on the line in a third-round match on Day 5 against No. 28 Jan-Lennard Struff. It's a rematch: Djokovic beat Struff 6-3, 6-1 last week at the Western & Southern Open, part of the 17-time Grand Slam champion's 25-0 start to the season. In other men's play Friday, No. 4 seed Stefanos Tsitsipas faces No. 27 Borna Coric, and No. 5 Alexander Zverev faces No. 32 Adrian Mannarino. In a matchup between players who won 2015 junior titles at Flushing Meadows, No. 19 Taylor Fritz, a 22-year-old American, will play No. 12 Dennis Shapovalov, a 21-year-old Canadian. Five years ago, Fritz was the boys champ in singles, Shapovalov in doubles. On the women's side, 2018 champion Naomi Osaka plays Marta Kostyuk, while 63rd-ranked Jessica Pegula's debut in the third round of a Grand Slam tournament comes against two-time Wimbledon champion Petra Kvitova. "Honestly, I don't even think I'm playing that great. I'm figuring it out," Pegula said. "Maybe before, I would have gotten more easily frustrated or not played as smart. I'm staying tough in the really tough moments." KEY RESULTS Men's second round: No. 2 Dominic Thiem beat Sumit Nagal 6-3, 6-3, 6-2; No. 3 Daniil Medvedev beat Christopher O'Connell 6-3, 6-2, 6-4; No. 6 Matteo Berrettini beat Ugo Humbert 6-4, 6-4, 7-6 (6); No. 21 Alex de Minaur beat Richard Gasquet 6-4, 6-3, 6-7 (6), 7-5; Vasek Pospisil beat No. 25 Milos Raonic 6-7 (1), 6-3, 7-6 (4), 6-3; No. 31 Marin Cilic beat Norbert Gombos 6-3, 1-6, 7-6 (2), 7-5. Women's second round: No. 2 Sofia Kenin beat Leylah Fernandez 6-4, 6-4; No. 3 Serena Williams beat Margarita Gasparyan 6-2, 6-4; Sorana Cirstea beat No. 9 Johanna Konta 2-6, 7-6 (5), 6-4; Tsvetana Pironkova beat No. 10 Garbiñe Muguruza 7-5, 6-3, No. 22 Amanda Anisimova beat Katrina Scott 4-6, 6-4, 6-1.

STAT OF THE DAY 111-110 — Konta's edge in total points in her loss to Cirstea. QUOTE OF THE DAY "I kept thinking, like, 'Oh, my gosh. I can't believe this is the U.S. Open. Where is everybody?' It's definitely, like, a huge bummer. I'm not going to lie, pretend like it's not, because it is." AP KHS KHS KHS