Former champion Carlos Alcaraz was dumped out of the U.S. Open in a stunning straight-sets defeat by world number 74 Botic van de Zandschulp on Thursday, while top seeds Jannik Sinner and Iga Swiatek moved on to the third round with little fuss.

Spanish third seed Alcaraz was fully expected to extend his 15-match winning streak at the Grand Slams but the Wimbledon and French Open champion got off to a horrible start and never recovered, going down 6-1 7-5 6-4 in the second round.

Van de Zandschulp, the first Dutchman to defeat a player in the top three at a major since Richard Krajicek beat Pete Sampras in the 1996 Wimbledon quarters, will next play Britain’s Jack Draper.

“It was a fight against myself, you know, in my mind during the match. In tennis you are playing against someone that wants the same as you,” said Alcaraz.

“Today I was playing against the opponent, and I was playing against myself.”

The 21-year-old was on the back foot early on as Van de Zandschulp claimed the opening three games with some resolute defending from the back of the court, and the Dutchman broke again in the sixth game en route to taking the first set.

Alcaraz produced a stunning forehand pass to hold serve in the first game of the next set but the four-times major winner’s struggles to close out points resurfaced as Van de Zandschulp broke for a 2-1 lead.

A tactical tweak to return serve from deeper helped Alcaraz break back immediately but the 2022 champion gifted his opponent another break with a double fault and Van de Zandschulp went on to comfortably double his advantage in the match.

After briefly leaving the court before the third set, Alcaraz found himself in deeper trouble after a wayward forehand handed Van de Zandschulp a break.

He hit back immediately and found his smile again, but world number 74 Van de Zandschulp got his nose in front and completed a stunning upset on serve.

“I didn’t feel well hitting the ball,” Alcaraz added. “I think I made a lot of mistakes and when I wanted to come back … it was too late.”

Former New York quarter-finalist Van de Zandschulp, hampered by injuries to his left foot in the last two years, was lost for words after the biggest victory of his career.

“It’s been an incredible evening. First time for me having a night session on Arthur Ashe. The crowd was amazing. Thank you for that. Unbelievable night,” said Van de Zandschulp.

“I think from point one here today I believed (I had) a chance. I had some nerves but if you want to beat one of these guys you have to be unbelievably calm and keep your head there.”

Van de Zandschulp will next face Britain’s Jack Draper.

There was far less drama earlier in the day at Arthur Ashe Stadium, where Poland’s Swiatek swatted aside Japanese qualifier Ena Shibahara 6-0 6-1 in a little over an hour. She plays unseeded Russian Anastasia Pavlyuchenkova next.

Australian Open winner Sinner was similarly untroubled in dispatching American Alex Michelsen 6-4 6-0 6-2, taking just 99 minutes to complete his ATP Tour-leading 30th hardcourt win of the year.

The Italian, who will play Australian Chris O’Connell next, has been dogged by controversy at Flushing Meadows after it was revealed days before the tournament he escaped a ban and was cleared of wrongdoing despite failing two drug tests this year.

He said he tested positive for a banned substance after his physio applied an over-the-counter spray to a cut on his own hand before carrying out treatments in March.

Sinner fired both his physio and trainer last week.

“Not easy, obviously, to find now in the middle of the season, you know, the physical trainer and the physio,” said Sinner. “We try our best to find the best people, and then we see.”

Twice champion Naomi Osaka was sent packing by Czech Karolina Muchova 6-3 7-6(5), another disappointing Grand Slam exit in what she has dubbed her “learning year” after coming back from a 15-month maternity break.

“I feel like I’m working way harder than I’ve ever worked in my life, so it needs to turn into something,” said Osaka. “Well, it doesn’t need to, but I think it will.”

Muchova, a semi-finalist last year, will next play Russian Anastasia Potapova.

Former champion Daniil Medvedev moved past Hungarian Fabian Marozsan 6-3 6-2 7-6, helped by his opponent’s 45 unforced errors, and will next play Italian Flavio Cobolli.

Sixth seed Jessica Pegula and 14th seed Tommy Paul boosted home hopes as both Americans advanced to the third round but compatriot Sebastian Korda crashed out.

Defending champion Coco Gauff will hope to keep the good times rolling for the home crowd when she opens up the action at Arthur Ashe against Ukrainian Elina Svitolina on Friday.

Ben Shelton and Frances Tiafoe promise fireworks in an all-American third-round clash.