The players are back in the arena after their mid-session interval.

There's another five frames to play in this session - whatever happens, it's guaranteed that Zhao Xintong will be in front overnight.

Image source, PA Media

As well as being a big day for the two finalists, it's also a big day in the career of Bulgarian referee Desislava Bozhilova.

She is the second female referee to take charge of a World Championship final at the Crucible, and the first female to officiate a final at all three Triple Crown events.

"It's been my dream since I started," she told the BBC. "At the beginning I didn't believe it was possible, but once I started going to more and more events and improving and getting bigger games, all of a sudden it became possible. I'm excited to have this chance.

"The world final is a huge match, but at the same time, it's a match where I should just do what I always do and that's how I've prepared for it.

"It does take a lot of [hard work] because you need to be able to constantly work on things, improve, keep concentration and listen to more experienced referees.

"I believe I've grown a lot as a person and as a referee. At the beginning you just know the rules, but you need the experience to be able to react to different situations and that comes with time."

Mark Williams played 97 of a possible 102 frames to make it to this year's final. He did it the hard way.

Zhao played 79 frames at the Crucible leading up to the final, although he played four rounds of qualifying just to make it into the main draw.

Zhao Xintong needed to get through four rounds of qualifying to get into the last 32, and has progressed impressively through the top half of the draw at the Crucible.

Jak Jones, the 2024 runner-up, was defeated by Zhao in the first round and remarked at the time that the Chinese left-hander would be difficult to stop.

So it has proved.

We told you earlier how WPBSA chief Jason Ferguson had told the BBC that Zhao Xintong will retain his ranking points and will break into the top 16 if he wins the world title (see post at 18:55 BST).

That would be bad news for current world number 16 Ali Carter, who has reposted this on X from fellow player Mark Allen - in response to the BBC interview - ironically suggesting Carter will be "buzzing" about the situation.

Shaun Murphy
2005 world champion on BBC Two

There was the hint of a small panic station but Zhao Xintong has totally weathered it now.

Jamie Broughton
BBC Radio 5 Live at the Crucible Theatre, Sheffield

Mark Williams needed a fast start tonight after being outplayed by Zhao Xintong in the opening session.

And the three-time world champion took his chances early on as the won the first two frames - with a break of 86 the highlight.

But Zhao then responded with a 71 break to go 8-3 up and followed up by winning the next.

We’ve got nine frames in this session and Williams will need to win most of them to stay in touch.

Zhao Xintong gets past the winning line and heads off to the interval where he started the session - six frames ahead.

He's now got half of the 18 frames he needs to become world champion.

John Virgo
1979 UK Championship winner on BBC Two

Mark seemed to have the perfect start by winning the first two frames, but he hasn't made any inroads into Zhao Xintong's lead.

Zhao Xintong's lead is up to 51 and all the remaining reds are in the open.

A 9-3 lead is surely a few moments away.

Shaun Murphy
2005 world champion on BBC Two

Zhao Xintong can take a little bit more time to get into things because of the great work this afternoon and now he'll be feeling OK.

I played him in the UK Championship and you can easily get mesmerised watching him play.

Spoke too soon - an awful positional shot on the next pink and Zhao Xintong has to play safe with an 18-point lead.

Yeah, he's back.

Zhao Xintong drills a long red into the corner at the start of the 12th frame and is away again.

However... he tries to bring out a few reds from the bunch off the black and sticks in them.

No harm done though, as he's just about on a red to the middle to keep the break going.

A settling break of 71 for Zhao Xintong, who has taken these very well.

The 11th frame is safe.

These first three frames of the evening have flown by.

Steve Sutcliffe
BBC Sport at the Crucible Theatre, Sheffield

I know that we keep referring to Zhao Xintong as an amateur, which of course he is officially, but he was the bookmakers' seventh favourite in the betting before this tournament began.

He previously won the UK Championship in 2021 and the German Masters in 2022 and looked set for great things until his burgeoning career was abruptly stopped when he was one of 10 players from China sanctioned in 2023 following an investigation into match-fixing.

Zhao did not directly throw a match, but he accepted charges of being a party to another player fixing two matches and betting on matches himself, and for those offences he received a 20-month ban.

He returned to action in September on the amateur Q Tour and has won events in Manchester, Sweden, Austria and Belgium, while he also qualified for the UK Championship and lost to Shaun Murphy in the first round.

His record this season, is played 48, won 46. He is a top, top player.

You have to keep your concentration when refereering a big final.

Referee Desislava Bozhilova is keeping an eye on the action here.

Image source, PA Media

Wow.

On 14, Zhao Xintong lets Mark Williams back to the table with a missed red.

A red and a black later, a dead-weight red along the top cushion stays in the jaws.

Tense.

John Parrott
1991 world champion on BBC Two

Mark came back against Judd Trump and he was 5-1 down to John Higgins in a best-of-25 before coming back to win.

The scoreline, to him, is sometimes immaterial. He'll keep playing every frame and see where it takes him.

At the moment, this is teetering on a comeback.

As Shaun Murphy said at the start of this frame, it would be understandable if Zhao Xintong starts to realise what he could be about to achieve and gets a little tight.

He's played a couple of iffy safety shots in this frame and a risky attempt at a plant does not go well either, giving Mark Williams a chance to reduce his deficit further.

Which he does.

A huge roar from the Crucible crowd - they want to see this score close up.