But a reprieve for Williams as Trump blasts a red, but it stays on the cloth and there's another red on.

Image source, Getty Images

With the black out of position, Williams is having to work hard to keep going for the pink. He does well to craft a break of 35, then not so well to miss a red and leave it on. Trump comes to the table 35-20 behind.

But Trump can't get position going from red to black and has to opt for safety having only pocketed 20.

Mark Williams perfectly rolls a red into the pocket and is nicely on the black, which is on its spot.

But a rueful shake of the head tells you he's missed it. Neither man has been two frames in front tonight. Trump will see this as a good chance to get into such a position.

BBC Four

Two more frames to be played tonight after the one that has just started - you can watch them live on BBC Four, the BBC iPlayer or by clicking the "Watch and listen" tab at the top of this page.

Image source, Getty Images

Williams can't get the second snooker and leaves a red to right middle and in it goes from Trump, who does the rest to nudge 3-2 in front.

Trump's 52 was the first half-century break from him tonight.

Williams gets to 32 and sticks the cue ball behind the blue. Trump misses from the one-cushion escape and that's one of the two snookers Williams needs. One more to go.

Trump stretches his lead to 72-0 and has to play safe, but Williams needs two four-point snookers as there are only 67 points on the table.

John Virgo
1979 UK Championship winner on BBC Four

Mark knows what an opportunity that was. If your opponent misses when they're in like that, you've got to punish them. A chance missed.

Judd Trump gets to 52 but misses a tough red to right middle, although Williams instantly misses a different red that was out in the open with his next shot. Chance missed for the Welshman.

Shaun Murphy
2005 world champion on BBC Four

I'm not sure if Judd went in the practice room - he usually does in the intervals just to keep that arm going.

This is probably just what he needed, with a highest break of just 41 so far in this match.

And we're back in action. Mark Williams has been the more attacking of the two so far, but this one doesn't pay off as a long red, hit with some pace, stays out with Trump getting an early opportunity to do some damage.

Here's a look at some of the recent champions...

Image source, PA Media

The BBC's Ask Me Anything team asked for your questions about snooker during the ongoing World Championship.

Some of those questions about the sport were put to World Snooker, who have provided responses.

SKP321 asked: Why don’t the refs have an iPad with the same screen as the marker when replacing balls?

A: Nice idea! But it wouldn’t be practical for the referee to carry an iPad and the process of replacing the balls is generally fast and efficient.

Richard asked: On TV, why do they only show the table in one perspective rather than above - where we get better judgement of the ball positioning as a viewer?

A: There are several cameras following the match, including those on the arena floor showing the angles from the pockets.

Matchroom Sport president Barry Hearn spoke to the media earlier on Thursday, following what he described as "productive" talks with Sheffield City Council regarding the future of the World Snooker Championship at the Crucible Theatre.

However, he said there is "still some way to go" before an agreement is reached to extend the existing deal which runs until 2027, and further discussions are planned for about three months' time.

Read more here and watch his BBC TV interview below.

Steve Sutcliffe
BBC Sport at the Crucible Theatre, Sheffield

Where I live in the UK, snooker venues have very much been disappearing over the past 10-15 years.

My old club is actually a bar that hosts tribute acts these days, while another I used to regularly play at is a performing arts centre. Can you believe it, eh?

Anyway, the audience and interest in the game is still definitely there. The global TV audience is now 650 million, which has doubled in the past 10 years.

World Snooker's digital following has doubled to more than five million in the previous five years and they have had 326 million views on TikTok alone this season.

Ticket sales for events are also higher than ever before with many venues sold out - no wonder Matchroom Sport president Barry Hearn is keen to maximise the sport's value and get a greater financial commitment towards keeping the World Championship at the Crucible beyond 2027.

Ken Doherty
1997 world champion on BBC Four

These players, at this level, make the game look so easy. But when there's that little bit of tension, it makes them look human.

Steve Davis
Six-time world champion on BBC Four

Image source, PA Media

The balls sometimes dictate how you play, then you get some tricky shots, you miss them and you're on the back foot because your confidence goes up and down.

It was a bit scrappy but then it's the first session of a big occasion and the stakes have been raised. It will develop, obviously.

It's not been the mini session we were hoping for, but Williams produces the first real bit of sustained quality with a superb 116, the first century of the match to get it back to 2-2.

He got to the pink, but overcooked the pot attempt with the ball ending up on the carpet.

At the interval, we're level.

A superb long red from Williams, one of the best shots of this match, and he could make a decent score here. Potential frame-winning chance.