Mark Allen won the last two frames to beat Marco Fu 6-5 in the quarter-finals of the UK Championship in York.
Qualifier Ricky Walden will be the Ulsterman’s opponent for a place in Sunday’s final after the Englishman knocked out former world champion Shaun Murphy 6-3.
In a topsy-turvy contest that could have gone either way, neither Allen nor Fu played anywhere near their best but still conjured up a thoroughly enthralling encounter that entertained the packed arena.
Northern Ireland’s Allen, who has been embroiled in controversy all week, took a protracted opening frame before doubling his lead at 2-0 to apparently seize control.
Yet, 2008 runner-up Fu, who looked all over the place at the beginning, gradually played his way into proceedings and fought back to two frames apiece at the interval.
The fifth frame provided a dramatic battle on a re-spotted black that saw the pair consecutively rattle the ball in the jaws of the pocket before Allen fluked a length-of-the-table double to retake the lead.
Former Premier League champion Fu fell two behind once again but won three on the trot to take the lead himself for the first time in the match, aided by a top run of 131 as well as stealing an eighth frame he should never have been allowed to claim on the black.
But despite only needing one frame to complete the turnaround there was a further twist as a 66 from Allen forced the week’s fifth decider and the 25 year-old sealed a memorable victory in the last to reach his sixth ranking event semi-final – a stage he is yet to progress past so far in his career.
Meanwhile, Walden, who beat another former world and UK champion in Mark Williams yesterday, was in control for the majority of his contest with Murphy.
The former Shanghai Masters champion fell 2-1 behind but claimed four frames on the trot to lead 5-2 and move to within one of victory.
While the 29 year-old undoubtedly played well, his opponent showed very little evidence of the form he had produced earlier in the tournament.
Indeed, the 2008 champion displayed a lot of the uncharacteristic traits that almost cost him his second round tie with Martin Gould at the tail end of that affair.
Murphy did reduce the arrears to two frames again at 5-3 but Walden seized his chance for glory in the subsequent one with a cool, nerveless break of 71.
For Chester’s Walden it completes a turnaround in fortunes that began in October by reaching the final of the Warsaw Classic and continued last week with a stunning 147 maximum at the German Masters qualifiers.
It also proves that those further down the rankings have the ability to mix it with the big names when their confidence isn’t in short supply.
Earlier in the day, Judd Trump and Neil Robertson advanced to the semi-finals in the top half of the draw – reports of their victories can be read here.
The full draw can be viewed by clicking here.