Ronnie O'Sullivan lost 4-1 on the first night of the British Open as Alexander Ursenbacher caused an early upset in Milton Keynes.
O'Sullivan had warmed up over the weekend in the World Mixed Doubles but showed no benefits here, failing to register a significant break against the Swiss youngster.
Ursenbacher had beaten O'Sullivan twice before and that experience surely counted for plenty as he built on a 69 break in the opening frame to take the second, before the world champion halved the deficit.
But a 51 break from Ursenbacher put him within one, earning James Cooper's followers a nice winner in the process, before he completed the job in another scrappy fifth frame.
Watched on by his mother, attending a match for the first time, a delighted Ursenbacher quipped: "It can't get any better than that - apparently I'm paying for dinner as well!
"I didn't think she was ever going to come over and actually watch me because of her work schedule, but my friend was going to come over anyway and they surprised me today. I was lying down on the street, I couldn't believe it! I thought there's no way I'm going to give in tonight.
"I was really nervous throughout the whole day. She's a good mum, the best mum you could ever wish for, but that puts pressure on you. If someone's done everything for you and thrown 26 years away, like every other parent, it gives you that extra pressure. You've got to make them proud."
Asked how he'd managed to make it three wins against O'Sullivan, he added: "I think against the best, it's the easiest way to push yourself. I don't know anyone who wouldn't want to play him.
"It's different when you're playing Higgins and Trump, they're just in the top three or whatever. He's the ultimate test, because he's the greatest player who's ever picked up a cue and ever will. Against him, I can't help myself but just give a hundred percent."
Stephen Hendry, working as pundit for ITV, was frank in his assessment of O'Sullivan's performance, saying: "That's probably the worst I've seen Ronnie play for a good few years. He was rubbish tonight."
Earlier in the day, Luca Brecel fell to a 4-1 defeat at the hands of Graeme Dott while Shaun Murphy crashed out after a black ball thriller with Gary Wilson, but it was O'Sullivan's exit which caused a stir, as Ursenbacher stole the show.