Nadal's out, while Kerber and Djokovic advance.
For the first time since 2004, Rafael Nadal will finish a calendar year without playing in a Grand Slam quarterfinals.
Nadal was upset on Sunday by Lucas Pouille, the 22-year-old Frenchman, in five sets at Arthur Ashe Stadium. Pouille won a fifth-set tiebreaker 8-6 to clinch a spot in the quarterfinals.
Angelique Kerber kicked off the night session with a straight-sets win over Petra Kvitova to advance to the U.S. Open quarterfinals for the second time in her career, and Novak Djokovic closed it out by beating Kyle Edmund in straight sets.
For results from Sunday's day session, including Caroline Wozniacki's victory over Madison Keys, check out SI.com's recap.
No. 24 Lucas Pouille d. No. 4 Rafael Nadal: Pouille upset the No. 4 seed 6-1, 2-6, 6-4, 3-6, 7-6(6) to reach the quarterfinals of a Slam for the second time this year and the second time of his career. Pouille will play Gael Monfils in the next round. For more information on this match, check out SI.com's complete recap.
No. 2 Angelique Kerber d. No. 14 Petra Kvitova: It was going to be tough to outdo the drama of the day session finale on Ashe, and it didn't—not that Angie Kerber will complain. The reigning Australian Open champion continued her excellent play on Sunday night, beating Petra Kvitova 6-3, 7-5.
"I think it was a tough match. It is always tough to find the rhythm against Petra," Kerber said. "She's just going for it. For me it was important to bring a lot of balls back, trying to moving good, and when I have the chance going for it."
Through four matches at the U.S. Open, Kerber hasn't dropped a set. She's playing as good as she has all season, and her third Grand Slam final of the year is within sight. Kerber continues to solidify herself as the clear No. 2 player on tour this season.
Kerber will face 2015 U.S. Open runner-up Roberta Vinci in the quarterfinals on Tuesday.
No. 1 Novak Djokovic d. Kyle Edmund: Djokovic hadn't played a full match since Monday, and he looked fresh on Sunday night as he beat Kyle Edmund 6-1, 6-1, 6-4 in just under two hours.
"It's good to play an entire match, considering I had not much time spent on the court in last couple rounds," Djokovic said after Sunday's match.
Edmund, who beat John Isner to reach the fourth round, was no match for Djokovic, who was especially good at the net, winning 17 of 18 net points. Edmund actually broke Djokovic twice, but Djokovic countered with eight breaks of his own.
Djokovic will face Jo-Wilfried Tsonga in the quarterfinals.
GIF of the Night
There are no words. Just nightmares.
Shot of the Night
Somehow, Rafael Nadal returned this Lucas Pouille overhead. I have no idea either.
U.S. Open Day 7 Snapshots
Check back tomorrow for the latest news and analysis on matches involving Serena Williams, Venus Williams, Andy Murray, Juan Martin del Potro and more.