Edbon sometimes took close on three minutes for each shot and dithered five minutes over a break of 12, which was almost as long as O'Sullivan needed to compile his fastest competitive 147.
During frame 17, the first one of the concluding session, O'Sullivan tried to counter Ebdon's delaying tactics by playing on despite needing 10 snookers.
He asked a member of the audience for the time, then in frame 20 laughed when Ebdon missed a pot and sat slumped in his chair with his hand covering his face, looking half asleep when his opponent was playing.
But it was Ebdon who gained from the histrionics for when O'Sullivan came to the table he was incapable of stringing together a sizeable break.
"Peter's got to do what he's got to do," said O'Sullivan. "He has a wife and four kids to feed. I was just very frustrated with my own performance." Asked about why he had played on when needing 10 snookers, O'Sullivan replied: "I was just trying to find some rhythm to carry into the next frame."
Ebdon, who now plays youngster Shaun Murphy in the semi-finals, denied he had tried to knock O'Sullivan out of his flow.
He said: "I was under tremendous pressure and I wasn't deliberately slowing Ronnie down. I didn't do it intentionally because I have so much respect for Ronnie. I put my heart and soul into every match I play and I just hung in there. I can't believe I won because I didn't play that well."
In tonight's other match, Matthew Stevens begins his fifth Crucible semi-final in six years when he takes on Ian McCulloch. Only once has he managed to reach the final, in 2000, and that ended in defeat by Welsh compatriot Mark Williams.
