Mark Selby crashed out of the Welsh Open after a 4-3 defeat to Liam Highfield in the last 64 on Wednesday.
The world number one’s position at the top of the rankings is now under threat after a disappointing season on the baize by his high standards.
Selby, who has been open in recent weeks about his struggles with depression, scored well to establish a 3-2 lead, but Highfield responded with excellent contributions of 74 and 92 to clinch it in a decider.
The latter was understandable happy about his performance as he reached the last 32 of a ranking event for the fifth time this season.
“The way I handled it was the most pleasing thing,” Highfield told the World Snooker Tour after knocking out reigning world champion Selby.
“I stayed calm throughout the match, took my chances, and made it difficult for Mark – I think the key with Mark is to stay patient.”
“But it is very hard, because my natural instinct is to sort of attack and be ultra aggressive and play that way.
“I think the key is to air on the side of a little bit more caution, because if you play open you can never get a chance – he’s so good at mopping up and so good at keeping you out.
“I held myself together really well towards the end, it was just a good break. I think I played the balls in the right order and played the right shots at the right times.
“On the back of those wins (previously against Selby), I’ve not gone on to have runs in tournaments which is what I’m after, so the next match against Michael White will be as tough.
“He’s a great player and we came through together in the junior ranks, so I’m looking forward to another match.
“You can’t raise your expectations because of one good victory, you’ve got to keep your feet on the ground and just get on with the job.”
Selby’s exit means Ronnie O’Sullivan has the opportunity to reclaim the number one position in the rankings for the first time since 2019.
The Rocket, who beat Lukas Kleckers on day three to set up an intriguing tie against Ding Junhui, can usurp Selby by claiming a fifth Welsh Open crown this week.
Meanwhile, several matches in the last 32 already took place on Wednesday as the busy schedule continued at the Celtic Manor Resort.
Neil Robertson and Judd Trump continued their progress in the tournament with respective victories over Graeme Dott and Si Jiahui.
In a battle of the former Welsh Open winners, Ali Carter denied John Higgins with breaks of 141, 87, 81, 51, and 50.
Home favourite Matthew Stevens secured a morale-boosting 4-0 triumph over Mitchell Mann that boosts the Welshman’s hopes of tour survival this term.
Joe Perry, Scott Donaldson, Jimmy Robertson, and Zhang Anda also moved on in the competition and through to the last 16.
By the end of the Thursday’s hectic order of play, the eight quarter-finalists in this year’s edition of the Welsh Open will be known.
Last 32 Draw Mitchell Mann 0-4 Matthew Stevens Zhang Anda 4-2 Yuan Sijun Hossein Vafaei vs Jak Jones Ryan Day vs Shaun Murphy Neil Robertson 4-1 Graeme Dott Barry Hawkins vs Ben Woollaston Jimmy Robertson 4-2 Fergal O'Brien Si Jiahui 2-4 Judd Trump Ronnie O'Sullivan vs Ding Junhui Yan Bingtao vs Ricky Walden Joe Perry 4-3 Mark Allen Matthew Selt vs Kyren Wilson John Higgins 2-4 Ali Carter Kurt Maflin 1-4 Scott Donaldson Jack Lisowski vs Elliot Slessor Michael White vs Liam Highfield
Live coverage is available on Eurosport, Quest, BBC Wales, or via other channels depending on your location.
Featured photo credit: WST