It happens at least once every US Open fortnight: the day session features three thrillers, matches that spill into the evening, generating a bonanza of late-night tennis that rolls past of the wee hours and into the early morning.

Day 6 of the 2017 US Open was just such a day – and just such a night.

The day session kicked off with a pair of barnburners on the women’s side – top-seeded Karolina Pliskova fought off a match point against Zhang Shuai to keep her title hopes alive and Coco Vandeweghe went nearly three hours to dust former world No. 2 Agnieszka Radwanska. That turned the day session over to Rafael Nadal, who dropped the opening stanza before righting the ship to put away lucky loser Leonardo Mayer in four.

Then came the fan exodus, the day session crowd emptying Arthur Ashe Stadium to usher in the evening attendees. And they were treated to some drama as well.

First, behind a flurry of nifty serves and whiplash forehands, Roger Federer dismissed Feliciano Lopez, 6-3, 6-3, 7-5, in a match of mid-30-somethings. And finally, closing it out at 1:45 a.m. – the second-latest finish for a women’s match in US Open history – was American Madison Keys, who polished off the day’s play with a come-from-behind, three-set victory over Elena Vesnina to become the fifth American women into the fourth round – the most for the U.S. at a major since the 2003 French Open.

Keys wrapped up the marathon day aptly in her post-match, on-court interview. When asked how she planned to prepare for No. 4 seed Elina Svitolina in the next round, Keys quipped: “I'm going to immediately get into bed and sleep until 3 o'clock tomorrow.”

play video Cognitive Highlight: Madison Keys - Round 3