Alexander Zverev and Daniil Medvedev return to action in the 2019 U.S. Open second round on Thursday, hoping they won't join the list of early upsets in the men's draw.

Five of the top 11 seeded men's players have been knocked out of the running at Flushing Meadows in New York. No. 5 Medvedev and No. 6 Zverev are respectively due to meet Hugo Dellien and Frances Tiafoe in the second round on Thursday afternoon.

Zverev was drawn in the same half of the bracket as Rafael Nadal—who faces wild card Thanasi Kokkinakis in the evening session—and could face the Spaniard in the quarter-finals should both men advance.

Women's champion Naomi Osaka resumes her title defence on Thursday and will look to beat Magda Linette in major competition for the second time this year.

Surprises have been harder to come by in the women's draw, though the likes of Simona Halep and Kiki Bertens will remain vigilant during their second-round ties.

Thursday's Key Afternoon Picks

Men's Singles

(5) Daniil Medvedev to beat Hugo Dellien

(6) Alexander Zverev to beat Frances Tiafoe

(14) John Isner to beat Jan-Lennard Struff

(25) Lucas Pouille to beat Dan Evans

Andrey Rublev to beat Gilles Simon

Women's Singles

(1) Naomi Osaka to beat Magda Linette

(4) Simona Halep to beat Taylor Townsend

(7) Kiki Bertens to beat Anastasia Pavlyuchenkova

Yulia Putintseva to beat (9) Aryna Sabalenka

(15) Bianca Andreescu to beat Kirsten Flipkens

Visit the U.S. Open website to see the draw in full.

Thursday TV Schedule

8 a.m.-11 a.m. ET, Tennis Channel

11 a.m.-11 p.m. ET (second round), ESPN 3/ESPN+

12 p.m.-6 p.m. ET (second round), ESPN

6 p.m.-7 p.m. ET (second round), ESPN 2

7 p.m.-11 p.m. ET (prime time), ESPN 2

Visit the U.S. Open website for a full TV schedule.

Preview

Fourth seed Dominic Thiem was the biggest shock departure of the U.S. Open first round, losing to the unseeded Thomas Fabbiano in four sets.

Consequently, Medvedev and Zverev will be wary given they are seeded directly behind the Austrian.

Zverev, 22, broke new ground reaching the U.S. Open third round in 2018 and will be hopeful of bettering that achievement this year. Similarly, his opponent on Thursday reached the competition's second round for the first time in 2018, so Tiafoe has his own career-best opportunity in sight.

Ivo Karlovic retired two sets down to the American in their first-round meeting. Live Tennis highlighted the disparity in playing time between his opening fixture and that of Zverev, who beat Radu Albot 6-1, 6-3, 4-6, 4-6, 6-2:

It's not the first time Zverev has expended a lot of energy early on at a Grand Slam—at the French Open, for example, his first-round match with the unseeded John Millman went five sets and two tiebreaks.

Medvedev, 23, looked more at ease during his 6-4, 6-1, 6-2 victory over Prajnesh Gunneswaran, and the rising Russian star should have a similarly simple task against Bolivian underdog Dellien.

His compatriot Andrey Rublev, 21, is another prospect worth watching; tennis writer Ben Rothenberg was impressed after he overcame eighth seed Stefanos Tsitsipas:

Rublev takes on Frenchman Gilles Simon, hoping to progress into the U.S. Open third round for a second year running (in only his third appearance). His opponent, meanwhile, hasn't made it to that stage since 2014.

Osaka's first-round win over Anna Blinkova (6-4, 6-7 (5), 6-2) wasn't the routine result she might have sought but at least ended the possibility of back-to-back first-round exits at majors for the Japanese.

The defending champion battled through a mid-match lull to take her place in the second round, and Osaka came across at ease in her post-match press conference:

Fans will hope that serenity carries through to her performances as she chases back-to-back crowns at the Billie Jean King National Tennis Center. She and Linette each have one win from their two meetings (both on hard surface), though Osaka triumphed in their most recent duel at the 2019 Australian Open.

Fourth seed Halep showed room for improvement in the first round, dropping a set against American Nicole Gibbs. She revealed after the 6-3, 3-6, 6-2 victory that she was feeling the stress levels:

The Romanian must beat another American in Taylor Townsend if she's to reach the third round, and she will feel confident considering she's won in each of their three past matchups.