Dubliner Ken Doherty, who has slumped to 15th in the provisional world rankings, received a much-needed boost at the British Open in Brighton today when he scored a 5-1 victory over temperamental Australian Quinten Hann.

Trailing 4-0 and clearly frustrated, Hann smashed the cue-ball into the pack of reds with his break off in the fifth frame.

He fluked a red to launch an 89 break that averted the whitewash but Doherty took the next frame to secure his place in the last 16.

Ronnie O'Sullivan, looking to complete a hat-trick of titles after closing last season by winning the Embassy World Championship, then opening this season by triumphing at the Grand Prix, reached the last 16 with a scrappy 5-2 victory over John Parrott.

But O'Sullivan was clearly unhappy with his performance during a contest that lasted two hours and 28 minutes and featured more than its share of tactical, disjointed exchanges.

The enigmatic star declared: "I was awful.

"If I keep playing like that they'll have to call the nuthouse to come and collect me.

"Whatever I do in my life I want to do it to the best of my ability and that kind of snooker is hard for me to take. I just don't enjoy it."

Three months after O'Sullivan turned professional at the age of 16 in 1992 his father Ronnie senior was sentenced to life for murder.

Twelve years later he remains behind bars and has never accompanied his son to a major tournament.

"I want my dad to have a look at me when he gets out so maybe I'll just do enough to stay in the top 16 until he's around then have another go," said O'Sullivan.

Stephen Lee also progressed with a hard fought 5-4 win over Mark King and now faces O'Sullivan, who remains the bookmakers' favourite to secure the title.