It's rare that two No. 1 seeds are eliminated before the quarterfinals of a Grand Slam. It's even rarer that they are eliminated on the same day in the fourth round.

Such was the case Sunday at the Australian Open, however, as both Andy Murray and Angelique Kerber lost. Below, we'll break down the day's action, highlighting the two stunning losses from the top seeds.

Men's Bracket

Murray's four-set loss to Mischa Zverev was another shock in Australia following Novak Djokovic's loss in the second round to Denis Istomin. The top seed also appeared to be a bit baffled following the match.

"It a tough loss at one of the biggest events and one that I wanted to do better at," he told BBC Sport. "I get a bit of time off now and try to learn from it and try to understand what I could have done a little bit better, and then come back and try again."

Zverev, of course, had a much different perspective after the contest.

"I was like in a little coma, just serving and volleying my way through it," he told BBC Sport. "There were a few points where I didn't know how I pulled it off, but somehow I made it. It was kind of easy to stay aggressive, but it was tough to stay calm. I was expecting to maybe double-fault in the last, but somehow I made it."

Murray likely won't be pleased with his 28 unforced errors, but this was hardly his worst performance. He wasn't his best, of course, but Zverev deserves credit for playing an excellent match.

He also had an excellent strategy. As ATPWorldTour.com wrote, Zverev's game plan was to "try to disrupt Murray's rhythm as much as possible, serving and volleying and slicing often against the top seed."

And if that didn't work?

"There was no Plan B, really," he said. "I can't stay on the baseline, a couple feet behind the baseline, try to out-rally him. He's very strong physically. He has a good baseline game. I knew I had to come in. That was my only chance to win."

Indeed, Zverev lived at the net, winning 65 of 118 net points. Now, he'll try to take his serve-and-volley approach to a deep, and surprising, run in Australia.

Up next, though, will be Roger Federer, who upset No. 5 Kei Nishikori on Sunday behind 24 aces and 83 winners and appeared to turn back the clock just a little bit.

Federer, of course, is always a threat. With Djokovic and Murray out of the way, he might have his best chance to win another Grand Slam before he ultimately retires. Yes, Stan Wawrinka—who needed three tiebreakers to get past Andreas Seppi—is always a threat. But Federer's top two foils are now out of his way.

It wouldn't be shocking to see him earn another title in Australia

Women's Bracket

Kerber didn't just lose Sunday; she was virtually brushed aside by Coco Vandeweghe, who won 78 percent of her first-serve points and slammed six aces and 30 winners in the straight-sets victory.

"I was trying everything, but I missed a lot and I make a lot of unforced errors," Kerber acknowledged after the match, per Greg Garber of ESPN.com. "So this was not my game."

Vandeweghe, meanwhile, never seemed intimidated by her top-ranked opponent.

"Going out there and playing an opponent, any opponent, I go out there expecting to win," she said. "It's just another person that's in front of me, whoever it may be, if it's No. 1 in the world, No. 130 in the world, it doesn't matter, it's still an opponent to get in my way of achieving my goals."

She certainly played that way.

Kerber wasn't the only upset, though, as No. 8 Svetlana Kuznetsova fell to No. 24 Anastasia Pavlyuchenkova. No. 13 Venus Williams and No. 7 Garbine Muguruza managed to avoid the upset trend of the day, however.

(Bleacher Report)