Tallon Griekspoor stunned top-seeded Alexander Zverev 4-6, 7-6 (7/5), 7-6 (7/4) in the second round at Indian Wells on Friday, avenging a devastating loss to the German at Roland Garros last year.
Zverev, the world No 2 who is heading the field of the prestigious ATP Masters event with No 1 Jannik Sinner serving a three-month drugs ban, is the first Indian Wells men's top seed to lose his opening match since Andy Murray in 2017.
The defeat in a tension-packed Stadium Court clash continued a lackluster run for Zverev since he fell to Sinner in the Australian Open final.
Since then the German had made early exits at Buenos Aires, Rio de Janeiro and Acapulco.
Broken to trail 5-6 in the third set, Zverev saved five match points in a dramatic 12th game, finally converting his fifth break point of the game to force the tiebreaker.
But Griekspoor sealed it on first chance in the decider, and the Dutch player was delighted to get it over the line against a player who had won their last five encounters, including four last year.
"It was such a mental thing," Griekspoor said, calling his loss to Zverev at Roland Garros last year – where he was up a double break in the fifth set – "absolute heartbreak".
"I played so many battles against him and had chances but they all went his way," said Griekspoor, who claimed his first victory over a top-five player in his 19th attempt.
"I am incredibly proud of myself from this performance and to get it over the line."
The see-saw battle saw Zverev rally from 2-5 down in the second set to take a 6-5 lead, but he was broken as he served for the match and Griekspoor made the most of a string of Zverev errors in the tiebreaker to pull level.
Griekspoor next faces France's Giovanni Mpetshi Perricard, the 29th seed who was leading 6-4 when Hungarian Fabien Marozsan retired from their second-round match.
MEDVEDEV UNDER THE LIGHTS
Russian Daniil Medvedev, runner-up to Carlos Alcaraz the past two years, headlines the night session taking on China's Bu Yunchaokete.
If he can finally break through for a first title in the California desert Medvedev would join Novak Djokovic and Roger Federer as the only men to win all of the current six ATP Masters hard court titles.
All 32 men's and women's seeds in the combined ATP Masters and WTA 1000 event had first-round byes.
Alcaraz, seeded second as he chases a third straight Indian Wells ATP title, launches his campaign against France's Quentin Halys on Saturday, when Djokovic, seeded sixth as he seeks a record-setting sixth title, faces Botic van de Zandschulp.