Ken Doherty
1997 world champion on BBC One

Mark Williams will be mightly relieved as Zhao Xintong had a few chances. He has gone off the boil slightly and he looked a bit edgy in that last frame before the interval.

Almost a great escape from a snooker from Zhao Xintong to leave a snooker of his own, but the brown moves just into a pottable position and Mark Williams sinks it.

The blue drops too and Williams has his first frame of the final as they head off for an interval.

Image source, Reuters

Mark Williams clears up to and including the green, leaving him 23 ahead with 22 remaining.

Zhao Xintong needs a snooker and he tucks Williams up behind the black - but the 50-year-old escapes.

This frame is not over yet.

Patrick: Zhao Xintong started well but you know Williams is going to be Williams soon and put a few together. I think this goes to frame 35 personally. Williams will still come through. Zhao is a true star though, would love him to win it. Could be snooker's Luke Littler.

Misses galore!

Zhao Xintong absolutely creams a long red into the corner, but then a black to the middle is off line.

Now it's Mark Williams at the table with a small deficit and three reds left, with only the brown in a safe position. Williams will probably need it if he's to win the frame in one visit.

Zhao Xintong breaks down by missing a tough brown, and then does the same with a green to the middle after fluking a red.

Good chance for Mark Williams here - but he just can't seem to find any rhythm. His highest break so far is just 30.

In commentary, Stephen Hendry comments that Zhao has gone off the boil slightly and that Williams winning a frame might settle both players down.

As well as the two finalists, it's a special day for referee Desislava Bozhilova.

Mark Williams has been outstanding with his long-potting in this World Championship but a missed red lets Zhao Xintong back in with a fairly easy starter.

4-0 incoming?

Mark Williams gets into an early lead in the fourth frame, which is the last one before the mid-session interval.

He's 16 points up and has Zhao Xintong snookered on all reds behind the brown.

Steve Sutcliffe
BBC Sport at the Crucible Theatre, Sheffield

Trish (left) is over from Dublin for the World Championship for the first time in nine years and couldn't wait for the action to get started, even if she was still waiting for a friend to turn up with the tickets just before play got under way.

"This is actually our our seventh or eighth World Championship," she said. "As the Trump and Williams match started I was fairly neutral but as it went on I started shouting for Williams. But I love the young lad Zhao Xintong, he is just sensational.

"I like the idea of the apprentice against the master."

Stephen Hendry
Seven-time world champion on BBC One

Mark would rather Zhao Xintong won that frame with a century break and he didn't have a chance rather than the way it transpired. This is a big frame now.

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Steve Davis
Six-time world champion on BBC One

Zhao has not flown in that frame so there is hope for Mark, but the confirmation you get from stealing a frame like that, when you should have lost it, makes you even more relaxed.

Mark Williams pots the green but leaves himself snookered on the brown, which he hits and leaves the cue ball tight on the cushion.

Zhao Xintong at the table now - long brown potted, cut-back blue potted, deep-screwed pink along the cushion potted. You will struggle to find three better pots in a row than that. Incredible.

The black rattles the jaws though! And then Mark Williams does likewise! Zhao cuts it in and now leads 3-0.

What a finale to that frame.

Zhao Xintong looked in position to win the frame but missed that green after taking evasive action from a fly.

Dennis Taylor
1985 world champion on BBC One

It's early days in this final but what an important frame this is.

Looks like the green will be the key ball in this frame.

Both players miss mid-distance attempts to pot it, then Zhao Xintong plays a superb snooker to leave Mark Williams behind the pink.

But it's a fine escape from Williams and the safety battle continues.

Stephen Hendry
Seven-time world champion on BBC One

This is the sort of frame that Mark Williams would be horrified to lose now because he's seen his opponent play a lot of bad shots and you can't let them get away with that.

Mark Williams, leading by 25 points, overcuts a red to the corner and leaves it over the pocket.

It is the length of the table and absolutely dead straight, but Zhao Xintong manages to screw back far enough to get on the black - phenomenal shot.

The 28-year-old from China lands awkwardly on the next red and needs a bit of side to pot it, sacrificing position - so much so that he has to play safe off the colour.

And it's not the best safety, so Williams has him back in trouble with his reply.

A few of you have asked this.

Answer: Yes, yes it is.

There have only been three left-handed world champions - Mark Williams, Neil Robertson and Judd Trump.

Image source, PA Media

Image source, PA Media

Stephen Hendry
Seven-time world champion on BBC One

It's been a very scrappy start to this final for Mark Williams.

The Welshman, playing in his fifth world final, misses a black with the rest.