Former world champion Ken Doherty discovered there's no such thing as an old pals act in sport when he bowed out of the Liverpool Victoria UK Championship against World Cup teammate Fergal O'Brien.

Doherty was coasting towards the quarter-finals when he led his practice partner and good friend 6-2 and 7-3.

But the world number four didn't win another frame as O'Brien reeled off six without reply to set-up a meeting with Dave Harold.

"It's going to take a long time to get over this defeat," said the 1994 UK Championship runner-up.

"I can't remember when I've collapsed quite as badly in a match before. Fergal didn't win the match, more I threw it away.

"There were a couple of crucial frames today I lost on the pink and black that I should have won.

"After that I couldn't do anything right, and Fergal went from strength to strength.

"It's not always easy playing someone you practice with, but I don't think that had any bearing on the game.

"Friendship goes out of the window once you get on the table."

O'Brien has now won three of their five career meetings but this was one of the sweetest. "I wasn't worried at 7-3," he claimed. "I just played the balls and let the outcome take care of itself.

"Ken didn't play well and missed a few balls, but I'm delighted by this result."

The highlight of O'Brien's comeback was a superb 130 break in frame 14 which brought him level for the first time since frame four.

He made a couple of vital 40 breaks in the final two frames to take his place in the last eight alongside world champion John Higgins.

The world number one moved closer to joining an exclusive club of players who have won the World and UK titles in the same year.

The 23-year-old Scot chalked up his second successive 9-4 win - this time against Northern Ireland's Terry Murphy - to set-up a meeting with John Parrott.