The 45-year-old took frequent breaks during the match which he lost 6-5.
Wilson summoned a nerveless 102 for victory after O’Sullivan who had looked ill at ease throughout their quarter-final clash, clawed back two frames in a row to haul the match level at 5-5.
The 45-year-old took frequent breaks throughout the match, insisting to referee Jan Verhaas that he was distracted by movement in the audience during frame-breaks in the second match in the two-table arena.
O’Sullivan also demanded a photographer be removed from the arena floor, but afterwards shrugged off the incidents and repeated his recent insistence that he “didn’t care” enough to make it a major issue.
O’Sullivan said: “I’d rather just sit down and wait. I said to the referee, we’re in no rush. I’m here to play snooker and there’s no time limit on how long the match takes.
“It doesn’t bother me. I play in good venues and bad venues, it is what it is. I don’t even care enough to have an opinion on it. It is what it is – just keep eating the smoked salmon and cream cheese.”
Wilson, seeking a place in his first UK semi-final and only a fourth win over O’Sullivan in 11 attempts, had got off to a flying start with breaks of 92 and 117 to establish a 2-0 lead.
O’Sullivan staged his first sit-down protest early in the fourth frame but it did little to detract from his momentum as he returned to polish off a century of his own and haul the match back level at 2-2.
After sharing the next two frames, O’Sullivan’s frustration boiled over again early in the seventh, when he insisted a photographer be removed from the arena.
Twice more O’Sullivan returned to his seat in the eighth frame, during a break in play in the match next door. O’Sullivan told Verhaas: “It’s the noise – I’d rather they all sit down, I’m in no rush.”
A rash safety from O’Sullivan allowed Wilson to produce a 39 clearance and move one frame from victory, but he blew his first chance of wrapping up the win after running out of position on a break of 35.
O’Sullivan duly summoned a 64 clearance to reduce the deficit to one frame, then forced the decider with a cool clearance of 83, punctuated by another short break as the action ebbed on the other table.
But it was Wilson who rose to the occasion, clenching his fist midway through his final-frame century which sealed a last-four clash against Belgium’s Luca Brecel, who beat Anthony McGill 6-2.
Wilson said: “I’m super-proud. At 5-3 things were starting to go a little bit against me and it’s only human to start to think your time has gone.
“I’m kind of fighting myself and starting to think I could have won this one, I’ve let another one slip against him, because I have let a couple slip against Ronnie, so to hold it together and take it out convincingly, there’s no better feeling.”
Wilson insisted he was not distracted by O’Sullivan’s antics, but admitted: “I just wanted to get on with it.
“I understand his reasoning for that. But when the crowd were up on my turn I just got on with it and I did a pretty good job.”