There will be no fourth instalment of Ronnie versus Judd in the Northern Ireland Open final, after O'Sullivan was knocked out on Thursday.
Trump has beaten O'Sullivan 9-7 in each of the last three finals, one of which took place in Milton Keynes, but O'Sullivan's hopes of revenge were ended when Yan Bingtao edged to a 4-3 victory in Belfast.
Yan capitalised on a surprise missed pink from O'Sullivan, who scored the game's only century and wasn't behind until frame five, before forcing a decider by pinching a tight sixth frame.
The Masters champion held his nerve in a scrappy final frame and will face Mitchell Mann next.
Trump, meanwhile, held off a fightback from Jimmy Robertson to edge through 4-3 in his quest for a fourth successive Northern Ireland crown and book a quarter-final against home favourite Mark Allen who beat Stephen Maguire in a decider after the Scot battled back from 3-1 down.
"I'm very happy, today is a very surprise victory," said Yan. "I missed a long pot, very good chance for Ronnie, I think 'game over'. He missed a surprising pink, gave me a very good chance."
During his 129 break in frame three, O'Sullivan became frustrated at movement in the crowd and took matters into his own hands, urging a spectator to "sit down", gesticulating with his hands, before saying it was "too much".
The referee intervened and asked stewards to not let fans into the auditorium during play.
"I think he made his feelings quite known," remarked Eurosport commentator and Sporting Life pundit Neal Foulds.
Earlier in the week, O'Sullivan clarified comments regarding the tournament which had appeared critical of the Belfast support.
O’Sullivan told Eurosport: "When I came here last time I said the atmosphere was flat – it’s never got anything to do with the crowd, the Belfast crowd and every crowd all over the world are so enthusiastic.
"It’s just that the set-up out there means you can’t get a good atmosphere because you can’t get anyone down the sides, so you feel like you’re playing to an empty auditorium.
"Every snooker fan is like family to me, so I’d never criticise any snooker fans. I don’t want any more enemies."
Also on Thursday afternoon, John Higgins fought back from a seemingly impossible position to beat 2017 champion Mark Williams 4-3.
Williams was in total command when 3-0 in front and still at 3-2, building a big lead in frame six, but Higgins stole it before completing the comeback against his fellow Class of 92 member.
“I was one ball away from losing at 3-0 behind. Mark will be kicking himself,” Higgins said. “Mark has beaten me the last few times we have played so it was good to get a little one back on him.”
