Potting machine Williams went into battle in the knowledge that he had already regained his world number one spot in the rankings from Ronnie O’Sullivan.

Lee was first amongst the balls on several occasions but he failed to capitalise and was destroyed by a ruthless performance from the 2000 champion, who had dropped just 11 frames on his way to the last four.

The Wiltshire-based player looked in a strong position in the opening frame courtesy of a 61 break but, after Williams had retaliated with a 38, he then missed an easy yellow and the Welshman cleared the colours.

World number seven Lee was also well placed in the next but failed to pot a straightforward red into the middle and in stepped Williams with a splendid 102 to the final black.

In frame three the scenario was similar with Lee in a healthy position when leading 47-9 – but a run of 53 edged Williams home. Then the pre interval whitewash was completed with a break of 35 from Williams proving decisive.

The same pattern continued after the break as a run of 47 was sufficient to put Williams 5-0 ahead. Another 47 to the blue enabled him to again come from behind to triumph in the next.

The prospect of a second session whitewash of the tournament after Doherty’s demolition of John Higgins in the quarter-finals was looming.

But Lee put paid to Williams’ chances of achieving that with a superb 140 clearance in frame seven which was started with a superb long red into the yellow pocket.

But normal service was resumed for Williams in the last frame with the aid of a 63 break to leave Lee with a mountain to climb.

In the afternoon session local favourite Hunter established a commanding position against Doherty to boost his chances of reaching a first world final.

Hunter, bidding to become the first Yorkshireman since Joe Johnson in 1986 to take the title, lived up to his pre-match tag of 8-11 on to triumph over the Irishman.

It was not a high-scoring affair with Doherty having the highest break of the session – 67 in the third frame – while Hunter’s best runs were 62 the second and 52 in the fourth.

But it was the fourth frame which was the big talking point after the cue ball had clearly rolled slightly off course as Doherty tried to snooker Hunter behind the brown when leading 32-14.

That deviation allowed Hunter the chance to escape by hitting a red and he went onto claim a frame that Doherty had been favourite to win.

The concentration of the Dubliner seemed to be shaken and his only success after that was in a scrappy 50 minute sixth frame.

The table had been repositioned and reclothed overnight as the arena switched to a one-table set-up for the semi-final and final.

Table-fitters went into action as soon as the session finished to try and rectify the situation ahead of the Williams-Lee showdown.

A World Snooker spokesman said: “As the table settled into the floor of the arena, the baulk slate joint moved slightly and a few fragments of Plaster of Paris collected under the baize near the brown spot.

“Table fitters rectified the problem immediately after the session finished in time for the start of the second semi-final.”