By Steve SutcliffeBBC Sport at the Crucible Theatre

Last updated on .From the section Snooker

Mark Williams
Mark Williams will be the oldest Crucible semi-finalist since Ray Reardson in 1985
Venue: Crucible Theatre, Sheffield Dates: 16 April-2 May
Coverage: Watch live on BBC TV and Red Button with uninterrupted coverage on BBC iPlayer, the BBC Sport website and the BBC Sport app

Mark Williams beatYan Bingtao to reach his seventh World Championship semi-final.

The breaks of 62 and 102 gave China'sYan a 10-8 lead.

Williams made 135 on his way to levelling at 10-10) and then broke 78 to win the match.

The Welshman will face either Stuart or Judd in the last-four.

It was a great match to be a part of. A lot of people think I should win because I was 6-2 in front, but it is not in this format. Williams said that he was over the moon to make two breaks at the end.

In a meeting between two players at the opposite end of their careers, it had looked like the younger one was going to get the better of the older one.

Williams, who appeared to lose his way during several long tactical frames on Wednesday evening, never looked panicked and produced an excellent display of potting to play his way back into the match and win it.

  • Six-time champion O'Sullivan seals semi-final spot

He said that he deserved it because a lot of the matches have gone the other way.

I am playing as well as I have all season. There was no way I could have won if it had continued.

Williams has not been in the last four since winning the most recent of his titles.

The afternoon session was cut short at 17:30 BST to accommodate their return to action in the final session.

The four-time winner opened with a brilliant 123 break and led 8-5 before the other player made contributions of 63 and 53 to reduce his deficit to a solitary frame.

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