Ronnie O’Sullivan, who last lifted a trophy over a year ago, is contesting only his third ranked match since January.
O’Sullivan remains on course for an unprecedented eighth modern-era world title, establishing a 6-2 advantage over Si Jiahui after the opening session of their World Championship quarter-final.
Should the seven-time champion progress, a semi-final encounter with Zhao Xintong is most probable, given Zhao’s commanding position against Chris Wakelin.
China’s Zhao, 28, put on an authoritative display to extend his lead over Wakelin from 6-2 to 12-4 in their best-of-25-frame match.
Elsewhere, the showdown between four-time world champion John Higgins and three-time winner Mark Williams is tightly balanced at 8-8, setting up an intriguing final session on Wednesday.
In what is only his third ranked outing this year, O’Sullivan took a scrappy opening frame before Si responded with an impressive century.
Si, just 22, then endured a succession of uncharacteristic errors, allowing O’Sullivan—known as ‘The Rocket’—to surge ahead to 4-1, courtesy of three half-century breaks.
Although Si briefly closed the gap with a 60 break, a costly black-ball miss handed O’Sullivan the seventh frame.
The Englishman rounded off the session with a stylish 121, underlining his dominance.
In the remaining quarter-final, Judd Trump delivered exemplary potting, notching his 101st and 102nd century breaks of the season to claim a 5-3 lead over Luca Brecel.
Their best-of-25 duel resumes on Wednesday at 10:00 BST, alongside the resumption of the Higgins-Williams classic.
World number one Trump is now just one century away from equalling Neil Robertson’s single-season record of 103, set in 2013-14.
Though Trump led 5-1, 2022 champion Brecel responded strongly, producing breaks of 68 and 128 to keep the contest finely poised.
Between them, Mark Williams (left) and John Higgins have collected seven world titles.
Higgins and Williams are part of snooker’s esteemed ‘Class of 92’, alongside O’Sullivan.
Williams, 50, is now the oldest Crucible quarter-finalist since Steve Davis in 2010, while Higgins will turn 50 just days after this year’s final.
Despite their ages, both remain among snooker’s elite, with their current battle recalling their memorable 2018 final, which Williams edged 18-16.
Higgins carved out a 5-1 early lead with four half-century breaks, yet Williams responded by claiming six of the next seven frames, highlighted by a 104 in frame seven.
Higgins, the world number three, rallied to win the 14th and, with a 70 break, moved 8-7 ahead.
However, a missed red in frame 16 allowed Williams to compile a 65 and square the match once again.
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Tuesday’s action: Full coverage from day 11 at the Crucible
Zhao’s scintillating form versus Wakelin suggests he could achieve the unprecedented feat of becoming the first amateur Crucible winner.
Having defeated former champion Neil Robertson and ex-world number one Mark Allen in prior rounds, Wakelin was comprehensively outplayed during both of Tuesday’s sessions.
Wakelin, 33, opened with a break of 93, but Zhao responded emphatically with six straight frames thereafter.
That momentum continued into the evening, with Zhao, 28, storming toward a maiden semi-final berth.
Zhao, a past UK Championship winner, was among 10 Chinese players banned in a recent match-fixing investigation.
Though he did not fix matches himself, Zhao admitted being involved in the offences, including aiding another’s match-fixing and betting on matches, resulting in a 20-month suspension. Of those sanctioned, he is the only player to return to competition.
The ban cost Zhao his professional tour card, but he has already secured his full-time return for next season.
For the current World Championship, Zhao entered as an official amateur, battling through four qualifying rounds for his seventh match of this campaign.