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Chinese youth Si Jiahui took a 5-3 lead in an intriguing first session of his World Championship semi-final showdown with Luca Brecel.
The 20-year-old, who came through qualifying at the Crucible to make the latter stages, lost frame one, but produced back-to-back distances of 125, 102 and 97 to punish Brecel for the mistakes with a near flawless display of break construction.
However the Belgian, who beat seven-time champion Ronnie O’Sullivan in the quarter-finals, fought his way back to 4-3 before succumbing with a nail-biting finish in the final frame of the afternoon.
In a scrappy start to the opening frame, Brecel enjoyed the benefit of an outrageous fluke when he rattled pink in the jaws and watched the ball race down the table along the cushion before falling.
He went on to make 50 before losing the blue from his seat, although Si, the tournament’s youngest semi-finalist since O’Sullivan in 1996, was unable to stop him from taking the lead.
However, the youngster announced himself in style in the second, sinking a hard red to come in before compiling an imperious 125 break, and repeated the feat to take a 2-1 lead when, after the Belgian missed the yellow at 33-0, he cleared yet again in a visit of 102 to complete consecutive centuries.
He took a 3-1 lead at mid-session after a fourth frame arm-wrestling with both players missing two difficult reds into the center pockets before prevailing 103-29 courtesy of a 97 break.
The world number 80 stuttered briefly, missing a regulation red as he applied the right side to the cue ball in an attempt to develop the group after Brecel missed yet again, but eventually drew a messy fifth frame 103-3.
Si’s first notable blunder came in his next when, 53 runs into another seemingly decisive break, he stunned black to allow his opponent to the table, and his break of 72 stopped the rot.
After benefiting from an error, Brecel returned it almost immediately, following up a nice red along with a careless blue, but the Chinese player was just as profligate, leaving himself unable to see a flush as he attempted to build and taking seven tries to hit the named brown.
A second snooker and three more errors yielded a further 12 runs to leave the 28-year-old ahead 38-33, and he eventually fell back to within a frame of his opponent with a visit of 69.
The final frame of the session came with a sustained safety exchange, but it was Brecel who made the first move with a break of 33 before inexplicably missing the squad, though Si faltered to 43-34.
His opponent jingled a pink in the top pocket that would have tied the game at 4-4 and watched him roll in agony over center for the youngest to go up two.
Mark Allen finished off the opening verse of the other semi-final against Mark Selby on a high, winning the last three frames to take a 5-3 overnight lead.
A pass of 123 gave Selby the ideal start, but uncharacteristic errors in the battles for safety over the next two frames allowed his Northern Irish opponent to gain control with breaks of 63 and 66.
Selby missed a black from his point in the fourth frame but still went level at the half-time interval at 2-2 as it was Allen’s turn to alter his lines in a tactical exchange.
A break of 68 put Selby in the lead in a rough and tumble session and while Allen drew level, there was a hint of controversy when replays showed he brushed the red he was bridging on to make a tough pot.
The referee didn’t notice the foul while Allen didn’t acknowledge it, so – with players so keen to call attention to any wrongdoing when they’re at the table – the suggestion was the southpaw, who has won three ranking events in this season, he was oblivious to what he had done.
Selby had one visit to the table thereafter but his rival’s break of 64 left him adrift and Allen quickly finished the frame. Allen then finished the session with breaks of 60 and 78 to take the lead.
