World champion and top seed Karim Abdel Gawad suffered a surprise first round loss at the Professional Squash Association (PSA) US Open.
The Egyptian star found himself on the back-foot early on in his tie with New Zealand's Paul Coll, who won the opening two games of the match at Philadelphia's Drexel University.
Gawad hit back in the third game as he threatened to turn the match around, but Coll remained composed to seal an 11-8, 11-3, 6-11, 11-8 triumph.
"It's definitely one of the most significant wins of my career," said Coll.
"I've known for a long time that I'd be playing him.
"I've been working really hard during the off-season and I'm cashing in on some of that now - to beat someone like him in round one is huge.
"I stuck to my game plan and trusted in what I was doing.
"I knew he'd come out hard in the third but I got back into it in the fourth and hit the right lines and length.
"But I have to stay grounded, I can't just be happy with that win, there's plenty of squash left in this event and I want to go further."
Coll will now face the challenge of Omar Mosaad, with the Egyptian earning a straightforward 11-8, 11-6, 11-5 win over England's Chris Simpson.
Peru's Diego Elias also triumphed in straight games, overcoming Hong Kong's Max Lee 11-8, 13-11, 11-7 to set up a second round clash with Egypt's Marwan Elshorbagy.
Raneem El Welily progressed to the second round of the women's competition, but the Egyptian was forced to do so the hard way.
Having lost the opening games 12-10, 11-9 to Canadian qualifier Hollie Naughton, the former world number one bounced back from the brink of defeat by winning the next three 11-6, 11-1, 11-9.
Having survived a scare, El Welily will hope for a smoother second round tie.
The second seed will take on Wales' Tesni Evans, who beat Egypt's Heba El Torky 11-6, 11-4, 17-15.
Defending champion Camille Serme eased into the next round by beating American wildcard Haley Mendez.
The French player triumphed in straight games 11-2, 11-7, 11-8.
The World Series event continues tomorrow.