Zizou Bergs recorded the biggest win of his career after stunning Carlos Alcaraz in straight sets at the Shanghai Masters.

The Belgian world No.39 held his nerve throughout a tightly contested encounter to prevail 7-5, 7-6(4) after more than two hours on court. Bergs is the second player this year to beat Alcaraz while ranked outside the top 20, after Sebastian Korda at the Miami Masters. He is also the lowest-ranked player to beat the Spaniard since his fellow countryman, David Goffin, did so last season.

“It’s a level of disbelief and not feeling too much,” Bergs said of his shock win.

“We’re now one minute after a match, so it’s tough to calm down but I’m very happy.”

Coming into the match having won just two out of his 16 meetings against top 10 players, Bergs gave it his all against the world No.3 and refused to be disheartened when losing a break advantage in both sets. Overall, he won 79% of his first service points and produced 24 winners.

“I just felt like last week in Tokyo, I really was in good shape,” Bergs said of his form.

“I’m very happy with how I handled the tiebreak. It is never easy to get broken when you can serve for the match, but to get back into the tiebreak, play those key moments and serve big, I’m very happy.”

Bergs has also beaten Andrey Rublev and Felix Auger-Aliassime when they were ranked in the world’s top 10. However, his win over Alcaraz is a big step up.

“To have this moment is a relief,” he said.

“I really feel like now I can win against those guys, not just that I can play against them, I can win against them.

“It’s a matter of staying in the process, and trying to be better all the time. And that’s the only way to do it step by step.”

The shock win has wider implications for the men’s Tour. As a result of Alcaraz’s exit, Alexander Zverev is guaranteed to finish the season as world No.1 for the first time. It will be the first time a German player has achieved this milestone in ATP rankings history, and Zverev will be the oldest to do so for the first time, at 29.

“It’s been a fantastic season for me winning in Paris and New York and knowing that I will finish the year on top of the rankings is just a dream come true,” Zverev told atptour.com. “So much work and effort have been put into achieving this goal, especially after coming back from the ankle injury. I look forward to finishing the season in style.”

Zverev is still playing in Shanghai and will play Alexander Bublik next. Meanwhile, Bergs faces either defending champion Valentin Vacherot or Tommy Paul.