O’Sullivan’s maximum at the end of the fourth-round clash at the Barbican Centre was the 109th in the sport’s history and the 13th of the Englishman’s career – improving his own all-time record.
The 38-year-old, who had a scare when the final blue wobbled in the jaws of the middle pocket before dropping, is set to earn £44,000 for the break, which is the first maximum of the tournament.
Making the achievement even more remarkable is that the five-time world champion is playing on a broken left ankle, sustained while out running in Essex last week.
Even fellow players Stephen Maguire and David Morris briefly stopped their fourth-round encounter on the neighbouring table to watch another potting masterclass.
O’Sullivan, who rattled in four half-century breaks as well as his maximum as he swept aside Selt, will play Anthony McGill for a place in the semi-finals as he continues his hunt for a fifth UK Championship crown, and first since 2007.
Marco Fu and Shaun Murphy served up another dramatic encounter before the Hong Kong potter sealed his place in the quarter-finals with a 6-5 win.
Murphy beat Fu 10-9 in a tense 2008 final and the pair went the distance again yesterday, with the match being decided on the final black.
The Englishman had looked on course to seal a place in the last eight when he built a 5-3 lead – helped by a superb 137 in the fifth frame – but Fu battled back to level things up at 5-5.
Murphy again seemed to have the edge in the final frame but, after compiling a break of 54, he snookered himself on the final yellow and Fu did not let his opportunity slip, the 36-year-old potting all the colours to take the decider 74-62.
Judd Trump, the 2011 champion, overcame veteran Rod Lawler 6-3.
The Bristolian started off with a 102 break in the opener but then lost the next two frames.
However, Trump responded by winning five of the next six frames after that, sealing the win with another century, 112.