Luca Brecel completed an astonishing comeback to beat Si Jiahui 17-15 and reach the World Championship final.
Brecel trailed 14-5 early in the third session only to win 12 of the following 13 frames and complete one of the greatest turnarounds in Crucible history.
Never before had any player overturned a deficit of nine frames but Brecel did so emphatically, drawing level with Si and then powering into the lead with 11 in succession against a shellshocked opponent.
Si dug deep to keep the match alive with a brave 91, but Brecel edged the next to reach his first Crucible final at the age of 28.
Brecel had already won a final-frame decider in his opening match against Ricky Walden, held off a Mark Williams fightback and then rattled off seven frames in a row to beat Ronnie O'Sullivan 13-10 from 10-6 down.
Speaking to Eurosport, he said: "I was thinking of losing with a session to spare to be honest. Even at 14-8, 14-9, you're still so far behind, you don't really think of winning.
"When it got to 14-14 I started believing only then. I don't know how I did it but I was still very calm, even at the end."
On his opponent, who was seeking to become the youngest ever Crucible finalist, Brecel added: "It's the closest thing to perfection, the way he played. I said at the end to him, you're a superstar. That's all he needs to hear I think."
Asked by Ronnie O'Sullivan where Si ranks among the young Chinese players coming through, Brecel was unambiguous. "The way he played? The best. If he plays like that consistently then he's the best."
While Si's future may well be bright, Brecel's is much more immediate. He'll face Mark Allen or Mark Selby in the final, played across four sessions on Sunday and Monday.
The latest Brecel fightback came in two parts, first the five frames the Belgian took before the close on Friday, and then the six which followed on Saturday afternoon.
Resuming with a 14-10 lead, Si still had the match under his control but a break of 70 ensured that Brecel picked up where he left off, going on to capture all four frames before the mid-session interval to at last draw level.
Brecel returned from that to win the 29th frame without conceding a point and then capitalised on two poor misses from a rattled Si, first when a long way off with a thin black and then a regulation blue off its spot.
Si responded with his highest break since he'd moved 14-5 clear, a run which defied the match status and reignited his hopes, and a deciding frame was on the cards until he was unfortunate to run out of position in the next.
From there, Brecel escaped from a snooker and then produced a fabulous final red before holding his nerve to seal a place in the final.
Si, who will jump from 80th to 36th in the rankings, said: "I’m disappointed but my opponent played near perfect snooker for the last two sessions, and my safety wasn’t as good.
"I have realised I have some flaws in my game and I need to improve. I will go into next season confident and believing I can beat any player."
Third session
Luca Brecel kept his World Championship hopes alive with a stunning late rally in the third session of his semi-final with Si Jiahui at the Crucible, closing to 14-10 behind.
Having held sway in the first two sessions, dominating Friday morning's offering in particular, Si resumed in similarly impressive fashion as he continued his apparently serene march to Sunday's final.
However, Brecel hit back in some style as he reeled off the last five frames of the session with a breathtaking blitz that for the first time appeared leave its mark in his previously unflappable opponent.
That was no more evident than when Si missed a simple green off its spot in the final frame, cutting short a regulation clearance that would have meant he led 15-9 overnight. Instead, Brecel ended a fine evening's work by reducing his arrears to four.
The night began with a typically pinpoint 90 from Si which was quickly followed by breaks of 132, his fourth century of the match so far, and 90 as Brecel cut a frustrated figure in his chair.
At this point, Brecel found himself 14-5 behind and nine frames adrift – a deficit never before overturned at the Crucible – but to his credit, he finally burst into life when clearing the table with 108 in frame 20.
With some impetus to finally work with, the Belgian returned from the mid-session interval a man possessed and duly won the next frame, and the next, the latter thanks to a run of 60 that featured a number of fine pots, none better than an absurd thin cut to middle.
And he wasn't done yet. A further hand of 66 made it four frames on the spin as the middle pocket was this time treated to a daring double – and there was still time for more drama.
Brecel was again in first in the final frame of what was a pulsating session, but when he broke down on 53, Si looked set to counter and end the day nursing a significant advantage.
But for the first time, the magnitude of the moment and what he stands on the cusp of achieving told and he left a simple green in the jaws of the pocket, allowing Brecel to finish on a high and breathe new life into a match that promises to come to a thrilling crescendo in the Crucible Saturday afternoon.
Second session
Si Jiahui turned the screw against a frustrated Luca Brecel during the second session of their World Championship semi-final at the Crucible, surging into an 11-5 lead in the race to 17.
The Chinese debutant headed into Friday morning holding a 5-3 advantage, but by the mid-session interval he led 8-4 thanks to breaks of 52, 122 and 89, while Brecel won his solitary frame with a run of 65.
Brecel showed his frustrations as early as the first frame when hurling the cueball off the table with his cue following another unforced error, incurring a warning from referee Rob Spencer.
Si, on the other hand, was the model maturity once again, rarely missing a beat in another class-high display that leaves him six frames away from becoming the youngest player ever to contest a World Championship final.
His deadly long potting was again a feature of his work, and he moved five ahead when adding a run of 58.
Brecel broke the sequence of three losing frames in a row when taking frame 14, but he was far from foot-perfect and his ragged morning got worse as Si signed off in style.
Breaks of 55 and 71 ensured the 20-year-old didn't allow his opponent to limit the damage, stretching six frames clear to tighten his grip on the contest.
First session
Si Jiahui leads Luca Brecel 5-3 after a dramatic finish to the opening session of their World Championship semi-final at the Crucible.
Both players had their moments in an absorbing opening salvo, but Si will be relieved to take a lead into Friday having threatened to forge clear when leading 4-1, before very nearly letting his advantage slip as Brecel almost levelled at 4-4 in a nervy finish to proceedings.
An outrageous fluked pink opened the door for Brecel to take the first frame with a break of 50, but Si took control thereafter, producing a magnificent display of break-building as he knocked in back-to-back centuries and then followed up with a break of 97 to move 3-1 in front at the mid-session interval.
When Si won frame five and then added a run of 53 in the following frame, the Chinese youngster was seemingly making light of the biggest match of his career.
However, he missed a simple black of its spot, allowing Brecel to stop the rot with a 72 clearance to the pink, just before he added a break of 69 to reduce his arrears to 4-3.
The final frame of the session swung one way and then the other, both men finally cracking and making a host of unforced errors until Brecel missed the final pink to the green pocket.
Si held himself together to pot the final two colours, ensuring he has his nose in front in a match that promises plenty more drama between two of the sport's brightest, young talents.
Related snooker links
- World Championship draw and schedule
- Perfect Snooker Player
- Snooker's GOAT: O'Sullivan by the numbers
- O'Sullivan: One of a kind
- History of snooker's number ones
- Watch all the Crucible 147 breaks
- History of 147 breaks
- Crucible memories: Ronnie's finest hour
- Crucible memories: Higgins denies Trump
- Crucible memories: White a People's Champion
- Crucible memories: Johnson stuns Davis
- Crucible memories: Foulds' dream debut