Here are five things to watch for on day eight of the US Open on Monday
1. Labor Day Monday will mark the first Military Appreciation Day at Flushing Meadows, including discounted tickets for the military and appearances by high-ranking officers.
2. Unseeded American Jennifer Brady will face the toughest test of her unexpected run when she kicks off the day against top-seeded Czech Karolina Pliskova in the fourth round.
3. Also in the last 16, world number one Rafael Nadal faces Ukrainian Alexandr Dolgopolov, who attracted the attention of the Tennis Integrity Unit when he lost a match to a lower ranked opponent last month amid strange betting patterns.
4. Third seed Roger Federer continues his bid for a 20th Grand Slam title when the Swiss takes on German 33rd seed Philipp Kohlschreiber in the fourth round.
5. It could be another late night for American Madison Keys in the evening's final match on Arthur Ashe Stadium against Ukrainian Elina Svitolina. Her third round match ended at 1:46a.m. local time, just shy of the record of 2:26 a.m.