After securing a tight opening frame, Bingham surged into a 2-0 lead with a monster 131 break before O’Sullivan halved the deficit with a timely 59.
Bingham reeled off the next two frames for a 4-1 advantage but the Rocket posted an incredible 135 clearance in under seven minutes and then comfortably added the seventh frame to reduce the arrears to one.
The players shared the next two frames to leave the score poised at 5-4 in Bingham’s advantage before the world number 10 took the following frame to clinch an impressive victory.
Bingham will now meet Neil Robertson for a place in the final after the Australian hit a 128 break en route to thrashing Stephen Maguire 6-2 in Thursday’s other early match.
"6-2 was probably an unfair reflection on the match," said Robertson. "The table conditions weren't ideal so it's hard to criticise Stephen or I for some of the safety shots that were over-hit because there's nothing you can do about it.
"My best snooker is still to come so it should be a really good game with Stuart. It's best of 17 and a one table setup so it's brilliant to have got to the semis of the UK and have continued my consistent season."
In the other half of the draw, Mark Selby edged a late-night thriller against Barry Hawkins to seal his place in the semis.
World number two Selby had to recover from 5-3 down to secure a 6-5 win over Crucible finalist Hawkins.
"I wasn't on my game in the early stages, my timing was out," said Selby, "I did my best to chuck it away in the last frame but crawled over the line in the end. I was lucky not to leave Barry an easy pot when he had a free ball. "
Walden impressed against Allen to reach his second UK semi-final, having lost to Allen in the semis here in 2011.
Selby will next play Ricky Walden, who comfortably saw off Mark Allen 6-2 in the quarter-finals.
"Mark had some cue problems and I know he can play better than that," said Walden. "He would have been a lot stronger if his cue had been okay and I was lucky to be in that position. I did my job. I'm just ticking over but I am winning games despite not playing at my best. Everyone can win when they are playing well. "
Neil Robertson 6-2 Stephen Maguire
Stuart Bingham 6-4 Ronnie O’Sullivan
Mark Selby 6-5 Barry Hawkins
Ricky Walden 6-2 Mark Allen
Mark Selby v Ricky Walden
Neil Robertson v Stuart Bingham