MELBOURNE - Frances Tiafoe just kept shaking his head and calling the whole thing "crazy" and "unbelievable".

Which it all kind of is.

That he reached his first Grand Slam quarterfinal on his 21st birthday by beating No 20 seed Grigor Dimitrov 7-5, 7-6 (6), 6-7 (1), 7-5 at the Australian Open on Sunday.

That he did it with the hydrating help of pickle juice guzzled during changeovers to fend off cramps.

That his shirt-removing, biceps-slapping victory poses that pay homage to LeBron James have gone viral and might have caught the NBA superstar's attention.

And, most poignantly of all, that Tiafoe is delivering on the promise he made as a kid to his mother and father-immigrants from Sierra Leone in West Africa-that one day he'd be a success.

"I told my parents 10 years ago I was going to be a pro. I was going to change their life," Tiafoe said, fighting back tears after getting past Dimitrov, a two-time major semifinalist who is coached by Andre Agassi. "And now I'm in the quarters of a Grand Slam. I can't believe it."

He grabbed plenty of attention before Roger Federer's bid for a third consecutive title at Melbourne Park ended with a 6-7 (11), 7-6 (3), 7-5, 7-6 (5) loss to 20-year-old Stefanos Tsitsipas of Greece.

Tiafoe, who grew up around a tennis facility in Maryland where his father, whom he calls "Pops", was a maintenance man, proudly noted he has been able to buy two homes for his folks.

That background taught him what he considers valuable lessons.

"Look, I'm not saying you can't make it if you grew up from a wealthy situation. I mean, a ton of people have. But coming from a working background gave me an incentive, a reason to give, a reason to work every day, understand why you do it," he said.

"Obviously, it's how bad do you really want to be successful, essentially. Like, what does that really mean to you?"

The 39th-ranked Tiafoe had never been past the third round at a major until now. And what a challenge awaits on Tuesday: His quarterfinal match is against 17-time major champion Rafael Nadal.

"He's going to run me like crazy," Tiafoe said. "I've got to go to sleep now, matter of fact."

And then, in either a bit of false bravado or a harmless joke, he added: "Yeah, he better get ready."

The second-seeded Nadal had very little trouble moving on, beating Tomas Berdych 6-0, 6-1, 7-6(4) in a rematch of the 2010 Wimbledon final. On the other half of the men's bracket, 2018 Australian Open runner-up Marin Cilic was ousted by 22nd-seeded Roberto Bautista Agut 6-7 (6), 6-3, 6-2, 4-6, 6-4. Bautista Agut had been 0-9 in fourth-round matches at majors, and his first quarterfinal will come against Tsitsipas, another man making his debut in that round.

Associated Press