The Welshman followed the likes of Stephen Hendry and Jimmy White out of the tournament as Harold reached his third quarter-final of the new season.

He resumed with a 5-3 lead and never looked back after a 105 break in the second frame of the final session of their match.

"I know people don't rate me and I know the bookmakers don't rate me, but I don't mind being the underdog. I know my game is as good as anyone's when I'm playing well," said Harold, who won the Asian Open title five years ago.

He goes on to face Ken Doherty of Fergal O'Brien, while Williams was left to reflect on his poor form.

"If I keep playing like that I will struggle to stay in the top 16. I'm playing well enough in the club back home but I can't seem to handle the pressure when I get to the venue," the left-hander complained.

Former world champion John Parrott also reached the last eight, with a 9-6 victory over Bristol's Gary Ponting.

Parrott, seeking his first UK title since 1991, scored consistently well in the morning session to move 6-2 up with breaks of 60, 39, 61, 42, 54 and 47.

And the Liverpudlian secured the three frames he needed in the evening session to progress.

Couch takes seat in last eight

Matthew Couch continued his shock run as he wrapped up a 9-5 victory over Michael Holt.

The 24-year-old Humberside player built up a five-frame advantage but Holt knocked in excellent breaks of 86 and 76 to pull the contest back to 8-5 - and he should have got back within two frames of his rival, but unluckily went in-off after potting the final yellow.

Couch took advantage of Holt's misfortune to clinch his passage into the quarter-finals. His third win of the tournament guarantees him a cheque for £10,800 - easily the best of his professional career.

"I'm surprised to get this far," Couch admitted. "I'd never even been to the last 16 of a ranking tournament before I arrived in Bournemouth. "