In a meeting between two-thirds of snooker's iconic 'Class of '92' — with Ronnie O’Sullivan completing the legendary trio — it was Higgins who capitalised on a handful of uncharacteristic errors from Williams to edge in front.
Both players, boasting four world titles each, are chasing another deep Crucible run to add to their storied careers.
While Higgins and Williams exchanged frames in a typically cagey battle, Zhao Xintong made a far more decisive move against Chris Wakelin over the other table.
Wakelin, who had already stunned former world champions Neil Robertson and Mark Allen to reach his first Crucible quarter-final, made a bright start with a break of 93 to claim the opening frame.
However, 28-year-old Zhao responded with six consecutive frames of clinical snooker, establishing a commanding 6–1 lead before Wakelin steadied himself by taking the final frame of the session to trail 6–2.
Zhao’s run to the quarter-finals is all the more remarkable given his recent history. A former UK Championship winner, Zhao was one of ten Chinese players sanctioned in a match-fixing scandal last year.
Although he did not deliberately lose matches, he accepted charges relating to being complicit in another player's match-fixing and for betting on matches. He served a 20-month ban — the longest among those punished — and lost his place on the professional World Snooker Tour.
Despite officially competing at this tournament as an amateur, Zhao has already secured his return to the tour for next season, and his performances in Sheffield have demonstrated his formidable talent.
To reach this stage, Zhao had to come through four rounds of qualifying, making this already his seventh match of the competition — and arguably one of the most impressive stories of this year's championship.
Both quarter-final matches will resume later on Tuesday evening (19:00 BST), with semi-final places up for grabs.