Mark Williams survived an unlikely fightback to beat Mark Allen 10-5 and book a mouthwatering Tour Championship final with Ronnie O’Sullivan.

The Welshman raced into a 9-0 lead at Manchester Central, but then saw the Northern Irishman take five frames on the trot to delay the seemingly inevitable.

Asked if he had been worried, Williams told ITV3: “Absolutely. Nine-nil, you can’t lose really, but an hour later it’s 9-5, if he wins that one 9-6, then your bum is going, there’s no question.”

The three-time world champion imposed a stranglehold on the match from the off, winning the first two frames before successive breaks of 99, 105 and 112 – he missed the final red in the latter as he closed in on a maximum – made it 5-0 as things started to turn ugly for Allen.

Williams scrapped his way over the line in the sixth and eased further ahead in the seventh before completing a first-session whitewash.

He picked up where he had left off in the evening session, rattling in a clearance of 140 to go 9-0 ahead, but Allen stopped the rot with a break of 65 to avoid the whitewash.

With Williams appearing to lose concentration, Allen won the next four frames – the last of them with a break of 69 – to reduce the deficit to 9-5.

However, the 49-year-old regained his composure to compile a decisive 75 to make Sunday’s final.

Williams said: “If I had to pick, it would definitely be O’Sullivan to play. He’s the best player by a mile, but I’m not afraid to play him. I’m going to enjoy it.”

Ronnie O’Sullivan demolished Ali Carter 10-2 to win what had been termed a grudge match and reach the semi-finals of the Tour Championship.

The pair had not met since their ill-tempered meeting at the Masters final in January, which O’Sullivan won 10-7.

Carter accused O’Sullivan of “snotting all over the floor” and The Rocket responded by saying his opponent was “not a nice person” during an expletive-laden rant.

O’Sullivan refused to speak about Carter in his pre-game interview, letting his snooker do the talking in a one-sided contest in Manchester that was over within an hour of the mid-match break.

Carter never settled after missing an easy red in the opening frame which O’Sullivan punished by making a 77 break.

A scrappy 28-minute frame followed and O’Sullivan went to the interval 4-0 ahead after compiling breaks of 87 and 54.

Carter’s best in the first session was a meagre 13 and his senses seemed scrambled when he attempted to swerve around the yellow and struck one of two reds left on the table.

O’Sullivan capitalised with a frame-winning 51 and extended his advantage to 7-0 with breaks of 81 and 92 – those efforts taking a total 14 minutes.

Carter headed into the final frame of the afternoon session with the grim prospect of being whitewashed.

But he responded in superb fashion with a 141 clearance to eclipse Tom Ford’s 138 as the highest break of the tournament, placing him in prime position for a £10,000 bonus.

Carter closed out O’Sullivan again at the start of the evening session, with breaks of 36 and 70 reducing the deficit to 7-2.

It was a false dawn, however, as Carter ran out of position and missed a red for O’Sullivan to make a 62 clearance.

O’Sullivan then cashed in with a decisive 52 break after another Carter error had opened up the table.

Carter was put of his misery in the 12th frame as O’Sullivan compiled 67 before going in-off in the middle pocket, a rare mistake in a snooker masterclass.

Zhang Anda and Gary Wilson will resume their quarter-final on Thursday level at 4-4, with the winner meeting O’Sullivan in the last four.

Wilson won two frames on the black to lead 3-1 before Zhang fought back strongly in an even contest.

Four-time world champion Mark Selby threatened to quit snooker after losing in the Tour Championship to Gary Wilson, who also described his winning performance as “embarrassing”.

Wilson sealed a 10-8 victory with a clearance of 105, but both players were scathing about their performance in Manchester.

“I mean I was pathetic really, from start to finish,” Selby told ITV4. “Probably one of the worst games I’ve played as a professional. Definitely up there for sure.

“If I carry on playing like that, then yeah, I won’t be enjoying it and I will be choosing a different career for sure.

“Neither of us played great in the second session, Gary played well on Monday and deserved his 5-3 lead. Today neither of us played great. I was like that all match. I deserved to lose.

“I will give the World Championship a go, but if I keep playing like that, I’m not going to carry on.”

Wilson believes he will have to improve ahead of his quarter-final against Zhang Anda, telling ITV4: “I don’t know how I won to be honest. I’m just thankful Mark didn’t play very well because I was embarrassing.

“The cue action wasn’t even there yesterday – it may have looked a bit better but I just felt deep down all along, I was struggling. I was hitting everything really quick and snatchy and just tried to keep plugging away.”

Reminded that he had made breaks of 95, 98, 78 and 101 in taking a 5-3 lead from Monday’s opening session and must therefore have been cueing well, Wilson replied: “Incorrect.

“I was not cueing very well at all but I can score when I’m not cueing well. That was feeling really bad and it was feeling even worse today and that’s why I missed so many easy balls, gave him so many chances and lifelines.

“Really, if I’d been playing decent and Mark had played as bad as he did there, I should have won that 10-3, 10-4. It was that bad it became really close and I’m just thankful he didn’t play very well either.

“I’m not enjoying it but we go again on Thursday and I’m just hoping I can find something between now and then.”

Ali Carter will face bitter rival Ronnie O’Sullivan in the quarter-finals after holding off a spirited fightback from Barry Hawkins.

Carter raced into a 7-1 lead after Hawkins had won the opening frame, but the left-hander won seven of the first nine frames in the evening session, including taking the 17th frame on a respotted black after needing two snookers.

However, Carter held his nerve to win the next and seal a 10-8 victory which sets up a showdown with O’Sullivan, 11 weeks after the pair were involved in a war of words following the Masters final won by O’Sullivan.

“I relish the challenge now because he’s the best player ever to pick up a cue,” Carter told ITV4. “To play him in another quarter-final, I’ve played him in a final this year, I’m in the right place.”

Mark Williams produced a superb clearance of 66 in the deciding frame to edge out Tom Ford 10-9 and set up a quarter-final with Judd Trump.

“I was dead on my feet for the last hour and three quarters, I was absolutely shattered,” said Williams, who has just returned from a trip to China.

“I thought it was all over. Where that clearance in the last frame came from I do not know. It was probably one of the best clearances I’ve done.”