Ka Wai Cheung recovered from 3-1 down to defeat Ronnie O'Sullivan 4-3 in the first round of the 2026 Northern Ireland Open, securing the biggest victory of his professional career in Belfast. The world No. 110 won the final three frames as O'Sullivan's difficult run of results continued.
What happened to Ronnie O'Sullivan at the Northern Ireland Open?
O'Sullivan appeared to take control after losing a scrappy opening frame. Breaks of 56, 138 and 72 carried the seven-time world champion into a 3-1 lead and left him one frame from the last 32.
The match changed when O'Sullivan made only 16 in frame five before missing a red to a top corner. Cheung responded with an 88, added a 77 to force a decider and then held his nerve when another opportunity arrived.
How did Ka Wai Cheung complete the comeback?
O'Sullivan had the first scoring chance in the deciding frame but overcut a short-range blue to a middle pocket after reaching six points. Cheung answered with a composed break of 60, which proved sufficient to seal the 4-3 upset.
The closing sequence was decisive: Cheung produced breaks of 88, 77 and 60 across the final three frames. He did not merely survive O'Sullivan's missed chances; he converted them with three substantial visits under increasing pressure.
| Match phase | Key contribution | Score impact |
|---|---|---|
| Frames 2-4 | O'Sullivan: 56, 138 and 72 | O'Sullivan led 3-1 |
| Frame 5 | Cheung: 88 | O'Sullivan led 3-2 |
| Frame 6 | Cheung: 77 | Match tied 3-3 |
| Frame 7 | Cheung: 60 | Cheung won 4-3 |
Why is Cheung's victory so significant?
Cheung entered the tournament ranked 110th in the world. The 27-year-old from Hong Kong had been relegated from the professional tour at the end of the previous season, but he immediately regained his card through Q School.
His victory over O'Sullivan takes him into the last 32 of a ranking event for only the second time. He will next face either Stuart Bingham or Yao Pengcheng, with the result giving him an important opportunity to build ranking points toward his stated goal of reaching the top 64.
For O'Sullivan, the defeat extends an uneven opening to the season. He reached the Wuhan Open semifinals but subsequently lost in the first round of the Shenzhen Open and has now suffered another opening-round exit in Belfast.
Which seeded players advanced during the afternoon session?
Kyren Wilson halted the run of seeded defeats with a 4-0 victory over Ben Mertens. The 2024 Northern Ireland Open champion compiled a top break of 81 and advanced to a meeting with Thailand's Thepchaiya Un-Nooh.
Wilson's result carried added importance because he entered the week 23rd on the Race to the Crucible list. A deep ranking-event run would strengthen his position before the qualification places for the World Championship become increasingly prominent later in the season.
Daniel Wells added another upset by defeating Barry Hawkins 4-2. Breaks of 61 and 106 helped Wells secure a last-32 match against either Chang Bingyu or Ryan Day, while also supporting his attempt to remain inside the top 32 on the one-year list and qualify for the World Grand Prix.
Who else reached the last 32 in Belfast?
Jamie Jones defeated Chris Wakelin 4-1 with breaks of 64, 65 and 63. Pang Junxu beat Alfie Burden 4-2, while former world champion Luca Brecel continued his return to form with a 4-1 success against Lei Peifan.
David Gilbert delivered the session's most concentrated display of heavy scoring. He made three centuries—106, 111 and 104—in a 4-1 victory over Oliver Sykes.
| Winner | Opponent | Score | Notable scoring |
|---|---|---|---|
| Ka Wai Cheung | Ronnie O'Sullivan | 4-3 | 88, 77 and 60 in the final three frames |
| Kyren Wilson | Ben Mertens | 4-0 | Top break of 81 |
| Daniel Wells | Barry Hawkins | 4-2 | Breaks of 61 and 106 |
| Jamie Jones | Chris Wakelin | 4-1 | Breaks of 64, 65 and 63 |
| Pang Junxu | Alfie Burden | 4-2 | Advanced to the last 32 |
| Luca Brecel | Lei Peifan | 4-1 | Continued his improving form |
| David Gilbert | Oliver Sykes | 4-1 | Centuries of 106, 111 and 104 |
Why was this Northern Ireland Open session so unpredictable?
Before Wilson completed his victory, all seven top-16 players who had finished their first-round matches had been eliminated. Cheung's comeback against O'Sullivan and Wells' victory over Hawkins reinforced the danger of the best-of-seven opening-round format, where one missed opportunity can rapidly change an entire match.
The afternoon also produced a striking contrast. Several established names struggled to close matches, while Gilbert compiled three centuries in only five frames and Wilson completed a whitewash. The session combined major upsets with some of the tournament's strongest break-building.
What should fans watch next?
Cheung's next test against Bingham or Yao will show whether the momentum from his breakthrough victory can carry into another round. Wilson's meeting with Un-Nooh offers a sharp clash of styles, while Wells remains focused on the ranking points that could secure a World Grand Prix place.
The immediate question for O'Sullivan is whether he can rediscover consistency after surrendering a two-frame advantage. For the rest of the field, the opening-round results have made one point clear: reputation alone offers little protection in Belfast.
Who beat Ronnie O'Sullivan at the 2026 Northern Ireland Open?
World No. 110 Ka Wai Cheung defeated Ronnie O'Sullivan 4-3 in the first round in Belfast.
How far behind was Ka Wai Cheung?
Cheung trailed 3-1 before winning three consecutive frames with breaks of 88, 77 and 60.
What was Ronnie O'Sullivan's highest break?
O'Sullivan made a 138 in the third frame, alongside breaks of 56 and 72.
Who will Ka Wai Cheung play next?
Cheung will face either Stuart Bingham or Yao Pengcheng in the last 32.
Who made three centuries during the session?
David Gilbert compiled breaks of 106, 111 and 104 in a 4-1 victory over Oliver Sykes.
