After Zhao Xintong misses a blue off the spot, another chance slips by for Mark Williams. What would usually have been a routine starting red to the corner doesn't drop.

Zhao takes the first opportunity to bring a few reds into play and he's got a superb chance for a 6-1 lead.

Stephen Hendry
Seven-time world champion on BBC One

Image source, PA Media

Mark is off it this afternoon and Zhao Xintong could really put a marker down. He'll be eyeing up a 7-1 advantage - or 6-2 minimum. I wouldn't want to give this guy a four-frame advantage.

A careless safety shot from Zhao Xintong leaves Mark Williams with a chance of a tricky red with the rest into the corner.

Williams leaves it over the pocket and Zhao is in again.

Ken Doherty
1997 world champion on BBC One

These couple of frames before the end of the session are so important now for Mark Williams.

The answer is yes. A "body blow" for Mark Williams, says Dennis Taylor in commentary.

Zhao Xintong clears up to and including the pink to ensure he will be ahead at the end of the first session.

The question now is by how many frames Zhao will be leading when they return for the second session at 19:00 BST.

Mark WIlliams is unable to cut in the penultimate red so his break ends on 61, giving him a lead of 24.

The red stays over the pocket - can Zhao Xintong pinch frame six?

Five reds left and Mark Williams is on a break of 37 with the scores equal.

There are a couple close to the top cushion but he'll hope to win the frame at this visit.

Stephen Hendry
Seven-time world champion on BBC One

Mark doesn't want to be too far behind against this guy - Zhao can reel off four or five frames so quickly, and he's not hit full gear in this match, but it won't take him long to hit those heights.

Zhao gets in first in frame six but decides against going into the pack when a chance presents itself and eventually his break ends on 37.

Dennis Taylor
1985 world champion on BBC One

Four is always a nice number to get to. It means you won't be behind at the end of the first session and you can go about extending your lead.

Steve Davis
Six-time world champion on BBC One

Of the two players, Zhao has been the freer cueist. Mark is still on rocky territory but there is hope because Zhao isn't killing off every frame in one visit.

Just blue, pink and black on the table and Mark Williams needs one five-point snooker to be able to tie.

Zhao Xintong knocks in a long blue and that'll be it - 4-1 to the qualifier from China.

Dennis Taylor
1985 world champion on BBC One

Image source, PA Media

A terrific 57 break from Zhao Xintong but he should have clinched it.

Mark Williams returns to the table snookered on the last red and gives away six points by hitting the pink, so WIlliams needs two snookers to have a chance of winning the frame.

A plant on a red to the corner, a tough brown finds the middle pocket, and Zhao Xintong is back at the right end of the table.

Zhao's high-scoring has deserted him in the past couple of frames but here's a good chance to rediscover it - a superb long red to the top corner after splitting the bunch should be the platform to clinch the frame.

Mark Williams gets a bit unlucky not to land on a red after going to the bunch and his break ends with him 23 points in front.

Williams has still has not had a break above 30 in this final.

There are a few rolls in and out of the cluster of reds before Zhao Xintong spots a three-ball plant in the pack and slots it into the top corner pocket.

It's only worth one point but at least it breaks the stalemate.

And Zhao's safety off the black is not a good one, only just reaching the baulk line. Mark Williams pounces all over it to start what he hopes will be a frame-winning contribution.

The players are back out after their mid-session interval.

Four more frames to be played in the opening session, followed by another nine from 19:00 BST.

World Professional Billiards and Snooker Association (WPBSA) chairman Jason Ferguson, speaking to BBC One about what Zhao Xintong winning the world title might mean for him and his home country of China:

"I think he has the potential to become the biggest star in the sport. Certainly the earning opportunities for someone like him are immense. It's a huge nation.

"We are operating in cities almost 50% the size of the UK. He would go back as a national hero and would be incredible for the sport."

The third frame was a tactical battle won by Zhao Xintong, secured with some magnificent pots on the brown, blue and pink.

Steve Sutcliffe
BBC Sport at the Crucible Theatre, Sheffield

Zhao Xintong is already guaranteed £200,000 just for reaching the final.

And while he is currently playing under amateur status, that matters not when it comes to collecting prize money here.

He is returning to the main professional tour next season and has his eyes set on the £500,000 top prize and a place in history as the first world champion from China.

If he were to achieve that, he would move to 11th in the world rankings. If he is not holding the trophy come Monday night, he will find himself ranked 29th in the world.

Steve Davis
Six-time world champion on BBC One

Mark will have encouragement that his opponent couldn't push on after showing a little bit of weakness. He's not controlling the cue ball, that's for sure.

We were thinking if Zhao Xintong keeps going, it would be 4-0. But as it turned out, when it gets mistake-ridden, you feed off that and catch it yourself.

It's been an interesting mini-session, it's advantage Zhao, but maybe Mark goes into the practice room, shakes the nerves out of his arm and shakes off the enormity of what he's done to get here.

It's still been exciting, even though it's not been the greatest snooker.