Ronnie O'Sullivan out of Northern Ireland Open, beaten 4-3 by world No 110 Cheung Ka Wai

Ronnie O'Sullivan lost 4-3 to Hong Kong's Cheung Ka Wai, the world number 110, in the first round of the Northern Ireland Open in Belfast on Monday, after leading 3-1, the World Snooker Tour reported. It was O'Sullivan's first match in a UK event this season, and Cheung's best win of his career.

The Snooker calendar has every event this season.

How it went

Cheung took a scrappy opening frame. O'Sullivan then made breaks of 56, 138 and 72 to lead 3-1. In frame five he scored 16 before missing a red to a top corner, and Cheung punished him with 88, then made 77 to level at 3-3. In the decider O'Sullivan was on 6 when he overcut a short blue to the middle pocket, and Cheung closed it out with a 60.

"It's the best moment for me on the snooker tour," Cheung said. "To beat Ronnie here, I'm very happy."

O'Sullivan, 50, has played four events in China this season and reached the Wuhan Open semi-finals, but lost in the first round of the Shenzhen Open to Jiang Jun. He has called his poor form a "disease" he has yet to cure. Cheung, 27, lost his tour card last season and won it back at Q School. He plays Stuart Bingham or Yao Pengcheng in the last 32.

Seeds falling in Belfast

Before Kyren Wilson's match, all seven top-16 players who had finished their first-round matches had been knocked out, WST said.

Other first-round results

Kyren Wilson, champion here two years ago, top-scored with 81 and now plays Thepchaiya Un-Nooh. He is 23rd on the race to the Crucible and needs a deep run somewhere this season to avoid qualifying for the World Championship. David Gilbert made three centuries (106, 111, 104) against Sykes, and Daniel Wells (breaks of 61 and 106) meets Chang Bingyu or Ryan Day.

Watching from Pakistan

Belfast is four hours behind Pakistan until UK clocks go back on 25 October (then five hours), so add four hours to any session time WST lists to get PKT. WST lists streaming options on its how to watch page.