Judd Trump relinquished his two-year grip on snooker's number one spot as world champion Mark Selby returned to the summit for the first time since March 2019.
The 22-times ranking event winner Trump needed to reach the quarter-finals at Leicester's Morningside Arena to avoid losing the top ranking to Selby, but suffered a 3-2 defeat to world number 49 Elliot Slessor in the last 32.
It came on the same day he turned 32 as Slessor advanced to face Ali Carter in the last 16 on Friday evening.
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Selby moves back to the top despite losing 3-0 to Carter at the same stage of the season's second ranking event on Thursday night.
"There is nothing I can do. I've won enough tournaments to be world number one," said a rueful Trump, who made a highest break of only 33 in struggling with the conditions.
There's only so many tournaments you can win. I've won 11 over the past two years and I'm not number one so...hard lines.
Trump had held the position since August 2019, three months after he lifted his first world title in Sheffield with an 18-9 win over John Higgins in the final.
Trump has lifted 14 ranking titles in 28 months and has been a model of consistency, but the £500,000 first prize and 500,000 ranking points for winning the world title has helped four-times Crucible winner Selby surge back to the top.
It was a position he first held in September 2011 and for four straight years between February 2015 and March 2019
"I think I’ve performed a miracle to be No.1, not winning the Worlds in the last two years, with how heavy the ranking points are favoured in that tournament," explained Trump before the first British Open since 2004.
I’d be disappointed, not that I don’t think Mark deserves it, but quite clearly I’ve been the best player over the last two years. For him to overtake me is probably a little bit of a fault with the ranking system.
British Open last-16 draw
- Jimmy Robertson v Stephen Maguire
- David Gilbert v Hammad Miah
- Ali Carter v Elliot Slessor
- Ricky Walden v Ross Muir
- Lu Ning v Lukas Kleckers
- Zhang Jiankang v Mark Williams
- Joe O'Connor v Zhou Yuelong
- Hossein Vafaei v Gary Wilson
Northern Ireland Open
Walden fights back to beat Murphy in deciding frame
Northern Ireland Open
Northern Ireland Open LIVE - Higgins heads up evening action after Trump exit