Mark Allen’s UK Championship title defence fell at the first hurdle after he was beaten 6-5 by Ding Junhui on Saturday.
One of the tastiest ties of the opening round in York brought a repeat of last year’s final, in which Allen recovered from 6-1 down to prevail a 10-7 winner.
But world number 17 Ding, who narrowly missed out on automatic qualification for this year’s tournament, avenged that defeat 12 months on as he overturned a 4-2 deficit to prevail in a deciding frame.
The three-time UK champion’s victory was all the more remarkable considering he had contemplated withdrawing following a recent struggle with dizziness and a fever.
Fresh from landing his second Champion of Champions title last weekend, Allen reeled off three successive frames from 2-1 down with breaks of 106 and 60 putting him in control at 4-2 ahead.
Ding responded with runs of 79 and 63 to level, before producing a stunning 71 clearance to snatch the ninth frame on the black after Allen had been in first with 65.
The Pistol, who had not lost in the last 32 of this event since 2012, hit back with 70 to force a decider, but a missed red to the left centre enabled Ding to get over the line with a wonderful 102.
Next up for the 14-time ranking event winner is a showdown with Tom Ford, who also came through in a deciding frame against Noppon Saengkham.
The International Championship trailed 5-1 against the popular Thai, who hit breaks of 127, 126 and 100 along the way, but hit back before producing a brilliant 66 clearance from 55-3 down in the final frame to snatch victory on the pink.
Jamie Clarke also produced an inspired turnaround from 5-1 down to stun Kyren Wilson in a deciding frame.
The Welshman fought back from the brink of defeat, including an 80 break from 54-0 behind in frame nine, and a run of 76 saw him through.
That set up a showdown with compatriot Mark Williams, who overcame Fan Zhengyi 6-4 earlier in the day.
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UK Championship 2023 Day One Results
Saturday November 25
Mark Allen 5-6 Ding Junhui
Mark Williams 6-4 Fan Zhengyi
Tom Ford 6-5 Noppon Saengkham
Kyren Wilson 5-6 Jamie Clarke