Alexei Popyrin has revealed that he took Botic van de Zandschulp's surprise win over Carlos Alcaraz as a sign that he could upset Novak Djokovic at the US Open. The Australian ended up doing just that on Friday night, with a four-set victory sending him through to the fourth round at the expense of the 24-time Grand Slam champion.

Third seed Alcaraz was dumped out of the US Open in straight sets by world No.74 Van de Zandschulp, with the result sending shockwaves through Flushing Meadows.

On learning of the upset, Popyrin said: "I woke up in the morning and showed my girlfriend straight away in shock. It was crazy. Results like that happen. I thought to myself, why not me today?"

The unfancied Popyrin took that motivation with him to Arthur Ashe Stadium and unleashed it on Djokovic, who was unable to live with the 28th seed as he raced into a two-set lead.

Once Popyrin gained that advantage, he was determined not to become yet another player who came within striking distance of beating Djokovic only to suffer one of his trademark comebacks. And that gave him extra fire in his belly after Djokovic halved the deficit by winning the third set.

"There are countless times when he's come back from two sets to love down," said Popyrin. "And I didn't want to be one of those moments where Novak kind of stepped up and came back from two sets to love down. That was going through my head. It was kind of extra motivation for me not to do that and to win that fourth set."

The 25-year-old did eventually hold his nerve to come through 6-4 6-4 2-6 6-4 and reach the fourth round of a Grand Slam for the first time in his career. An easier test than Djokovic, at least on paper, awaits, but American Frances Tiafoe will benefit from the support of his home crowd.

"He's actually a really good friend of mine," said Popyrin. "We get along really well off the court. It will be interesting to play against him. We have practiced a bunch of times.

"Honestly, playing Frances will be quite an experience because there has been a few times where I have kind of lost the round before having to play Frances, and he's always telling me, 'Man, why do you keep losing before we play each other?'"