|Betway UK Championship|
|Venue: York Barbican Dates: 27 November-9 December|
|Coverage: Watch live across BBC Two, BBC iPlayer, BBC Red Button, Connected TV, the BBC Sport website and mobile app from 1 December.|
World number one Mark Selby suffered a 6-3 first-round loss to amateur James Cahill in one of the biggest shocks in recent UK Championship history.
The two-time former champion struggled throughout against the 22-year 126th seed, who dropped off the main tour at the end of the 2016-17 season.
Cahill led 4-0 and 5-1 and closed out the win by potting a superb long pink in frame nine.
“It’s a great win. Hopefully I can take confidence from that,” he said.
“The standard wasn’t amazing. But to beat the world number one, such a great player, is brilliant.
“I am good enough to compete with the best but I need to be more consistent.”
Cahill has not been past the first round of a ranking event this season but found his form at the York Barbican.
Selby, who lost to Scott Donaldson in the second round last season, managed just 79 points in the first four frames before getting on the board to rekindle hopes of a trademark comeback.
Cahill got his opponent in trouble on the colours and took the next frame by potting pink and black.
The Leicester man suddenly found his form, taking the next two frames and hitting a 103 along the way to reduce Cahill’s lead to 5-3.
But Cahill played a nerveless ninth frame to win through to round two, where he faces Sunny Akani.
“I was rubbish all match,” Selby said. “I am devastated because it’s a big tournament. I felt flat, which is strange.
“I have been playing well lately so to perform like that is strange. There aren’t many positives to take.”
While Selby struggled, fellow two-time UK winner and reigning world champion Mark Williams had little trouble in seeing off his amateur opponent, Adam Duffy.
The 43-year-old Welshman, the winner of 22 ranking titles, scored four half-centuries in a convincing 6-2 victory.
Williams, who has admitted he neglected his practice since winning the world title in May, showed few signs of rustiness.
“My performance was OK, but it was pretty scrappy stuff,” he said.
“If I could win this tournament three times it would be fantastic. This will probably be my last tournament before Christmas so I want to try to have a good run and see what happens.”
The second round of this year’s tournament begins on Saturday, 1 December, when live coverage is available across the BBC on BBC Two, BBC iPlayer, the Red Button, Connected TVs and on the BBC Sport website and app.
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