Ronnie O’Sullivan crashed out in the first round of the Northern Ireland Open in Belfast after he was beaten 4-3 by a qualifier ranked 110th in the world.

Cheung Ka Wai took the last three frames in succession to complete a victory that was his first in a main draw knockout match at a ranking event.

The defeat came in what was only O’Sullivan’s third tournament of the season, and his first match in the UK since he lost 13-12 to John Higgins in the second round of the World Championship in Sheffield in April.

The seven-time world champion, 50, made a 138 total clearance in the second frame, but a series of blunders let the Hong Kong qualifier in to take his chances and reach the second round.

O’Sullivan lost the opening frame, then showed few signs of rust by taking the next three with breaks of 56, 138 and 72.

Cheung, who joined the tour in 2024 and had previously won main draw matches only in the Championship League, appeared down and out when O’Sullivan got in first in the fifth frame.

But O’Sullivan left a red dangling over the bottom pocket, and Cheung responded with a superb break of 88.

He then pounced on a simple missed brown from O’Sullivan to summon a break of 77 and level the match. O’Sullivan was in first again in the decider, but missed a blue to the middle.

His inexperienced opponent carved out a match-winning break of 60 to heap more woe on the ailing O’Sullivan.

Cheung said: “It’s the best moment for me on the snooker tour. To be honest I was a little bit scared of playing him but my coach told me, whether I win or lose, to get the best experience possible.”

Back in April, O’Sullivan admitted he wanted to focus on financial incentives this season.

"Any tournament I go to, they all know they have to get the chequebook out," he stated. "If that stops, then I stop. Whenever it is – Saudi, Qatar, China, here, whatever it is – I always make sure I’ve got some sort of fee coming because otherwise people know that I won’t turn up."