Apart from that the two-time world champion could hardly pot a ball and he joined fellow heavyweights Ronnie O'Sullivan, Matthew Stevens, John Higgins and Ken Doherty in failing to reach the last 16.

"I can hardly put my performance into words - that's how bad it was," said the 29-year-old Welshman.

"I think the best word to use is brutal.

"My form has been like that for a while now, although not quite that bad. I'm just on a bad run and short of confidence. I need a few wins to get my confidence back up but I don't look like getting them.

"For the last three or four frames I felt like I wasn't out there. From the moment I walked through the curtain, I couldn't wait to go back through it again."

Williams, who became a father shortly before relinquishing the world title last season, held the sport's four top titles just over a year ago but has been on a downward spiral ever since.

"Motivation is definitely a problem for me," he admitted.

"It's hard work going to the club to practise, and I only do that every two or three days.

"I still enjoy playing matches but I'm just not practising enough. It's my own fault and it's up to me to turn it round. But if I had enough money I would never pick up a cue again."

King, the world number 23 from Romford, felt his victory was not purely down to Williams' failings.

"I didn't let him play," insisted King, who will meet Alan McManus for a place in the quarter-finals.

"My safety was some of the best I have ever produced. I put him in so much trouble. For Mark to say he played badly doesn't do justice to how I played."