US Open: Shocked Rafael Nadal not sure of his "return" after losing to Frances Tiafoe

American Frances Tiafoe registered a 6-4 4-6 6-4 6-3 victory against the Spanish maestro at the Arthur Ashe Stadium. He broke Nadal five times to cause the biggest upset of the Slam.

"I don't even know what to say right now; I'm beyond happy, I'm almost in tears," the 22nd-seeded Tiafoe exclaimed in an on-court interview. Tiafoe's display of brilliant tennis, coupled with a poor serving and returning performance from Nadal, culminated in the American's win.

Nadal hit nine double faults and only 33 winners to Tiafoe's 48. He broke Nadal's record of being at least a quarterfinalist in 17 straight majors. He had won the Australian and French Opens this year before injuries caught hold of the 36-year-old.

"I can find excuses but for me, it's simple: when you don't play at the level that you should, you can't win," Nadal said. "My opponent was the better player".

Tiafoe broke Nadal taking a 4-3 lead in the first set, and secured it despite having never won a set against the Spaniard in their last two meetings. The second was better for Nadal, who won when Tiafoe double faulted by a narrow margin.

Tiafoe converted a breakpoint in the third set by sending a backhand winner and taking a 4-3 lead. Nadal was leading 3-1 in the fourth set after Tiafoe lost his serve due to external issues prompting him to address in front of the chair umpire.

Tiafoe took advantage of a poor service game by Nadal and broke him in the last round when the Spaniard netted a backhand. Now, Tiafoe will face Andrew Rublev in the quarter-finals.

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