This is nervy.

Chances have been spurned in both the evening's opening frames, and Ben Woollaston's missed green proves decisive in the 10th frame of the match.

Thirteenth seed Si Jiahui goes two ahead again.

The winner of this match has a big quarter-final incentive - their likely opponent will be Ronnie O'Sullivan, who is 12-4 ahead and one frame away from beating Pang Junxu. That match concludes on Monday evening.

You work so hard to take a 43-minute opening frame, then break off and leave your opponent an easy starter into the middle.

Shaun Murphy will be so disappointed with that.

Judd Trump is off and running, racking up a lead of 30 points and counting in double-quick time.

Both players had plenty of chances in that opening frame but it's Shaun Murphy who gets over the line and reduces his deficit to 5-4.

Image source, Getty Images

John Parrott
1991 world champion on BBC Two

There's nothing wrong with a long frame - as long as you win it. It's when you put all of that effort in and you have nothing to show for it. As long as the scoreboard changes in your favour, you don't mind them.

I don't think we expected to see too many 40-minute frames between Judd Trump and Shaun Murphy, but that's what we have in the opening frame of this session.

Shaun Murphy pots the yellow after a lengthy safety exchange, and now the players are trying to make a decisive effort on the green.

With a few fouls thrown in, Murphy's lead is down to five points.

John Virgo
1979 UK Championship winner on BBC Two

Neither player at the moment is knocking in those mid-range pots.

Ben Woollaston will be a relieved man.

He breaks down on 67, which allows Si Jiahui in and he's looking good on 26 with the possibility of setting up a snooker later.

But OH NO...the cue ball drifts into the middle pocket after he pots the black, and his lead is reduced.

It's a very tactical frame to start the session and Shaun Murphy is 23 points ahead with just the colours left.

The blue, on its spot, is the closest ball to the baulk end.

Six reds remain on the table and Shaun Murphy has a one-point lead.

Michael Emons
BBC Sport at the Crucible Theatre

Image source, Michael Emons

It could be a very profitable few hours for both Shaun Murphy and Judd Trump.

Trump is two century breaks away from getting a £100,000 prize for making 100 centuries in the season.

Meanwhile, Murphy could also pocket himself £147,000 as that's what is on offer for any player to make two 147s from the Masters, UK Championship, Saudi Masters and World Championship.

Murphy made a 147 in his Masters semi-final against Mark Allen back in January so another one today would get him the money.

A sign of things to come?

Shaun Murphy plays a very attacking safety to kick off frame nine, splitting the pack of reds before returning to baulk, and it earns him a chance of a red to the middle pocket at his next visit.

It's not easy, but Murphy makes no mistake and will now set about trying to reduce his two-frame deficit.

The hope of doing that doesn't last long - Murphy adds only seven points before missing a brown.

Stephen Hendry
Seven-time world champion on BBC Two

Judd is the world number one and has been the best player in the world for the past three or four years, so he'll be wanting to cement that reputation by winning another two or three world titles.

It's a little bit unlucky for both of them to draw each other so early - this could easily have been a final.

The second session is always like moving day - like the Saturday of a major golf tournament. You want to try to get a lead going into the third and final session.

Ken Doherty
1997 world champion on BBC Two

Shaun started really fast and let Judd off the hook a little bit.

It's still beautifully poised. Two great players in great form and there will be a lot more great snooker tonight.

In what was arguably the most anticipated tie of the second round, world number one Judd Trump opened up a 5-3 lead against Masters champion Shaun Murphy this morning.

Murphy was 2-0 and 3-2 in front, helped by a break of 103 in frame five, but Trump took the final three frames of the first session to end it in front.

If these two reproduce some of the form we've seen from them at times this season, prepare for fireworks.

Si Jiahui resumes 5-3 up against qualifier Ben Woollaston after their first session on Saturday evening.

It has been a fairly even affair so far, with plenty of close frames that were settled by the colours.

However, there was only one break of 50 or above so both players will hope to improve on that side of the game if they possibly can today.

Michael Emons
BBC Sport at the Crucible Theatre

Image source, Getty Images

Ronnie O'Sullivan and Luca Brecel are both one frame away from making the quarter-finals of the World Championship as they hold 12-4 leads over Chinese duo Pang Junxu and Ding Junhui respectively.

O'Sullivan, 49, is aiming to become world champion for an eighth time for what would be a record in the modern era, while Brecel lifted the trophy at the Crucible two years ago. Both men will be looking to clinch quick victories when their matches resume at 19:00 BST on Monday.

O'Sullivan led 6-2 after the first session, although qualifier Pang pulled two frames back following breaks of 87 and 62. But O'Sullivan quickly regained his form as he won the remaining six frames on Sunday, aided by runs of 79, 80, 105, 135 and 62.

Belgian Brecel produced one of the most remarkable sessions at the Crucible on Saturday evening. Having arrived at the venue only 25 minutes before play was due to start after flying on a private jet from his home country, he lost the opening frame before winning seven in a row with a sensational display of attacking snooker.

He continued where he had left off on Sunday.

Scores of 53, 75 and 56 helped him win four consecutive frames to leave the score at 11-1, although Ding showed good character to take three of the next four, ending with back-to-back centuries of 107 and 110.

O'Sullivan and Brecel are in opposite halves of the draw so could only meet in the final.

10:00

• Lei Peifan 10-13 Zhao Xintong - Zhao to play Chris Wakelin in quarter-final
• Shaun Murphy 3-5 Judd Trump - resumes on Sunday at 19:00 BST

14:30

• Ronnie O'Sullivan 12-4 Pang Junxu - resumes on Monday at 19:00 BST
• Luca Brecel 12-4 Ding Junhui - resumes on Monday at 19:00 BST

19:00

• Si Jiahui 5-3 Ben Woollaston - frames 9-16
• Shaun Murphy 3-5 Judd Trump - frames 9-16

BBC Two

And... we're back.

Play is about to resume in Sheffield, with coverage starting on BBC Two at 19:00 BST.

Both matches are available to watch live on the BBC iPlayer and via the "Watch and listen" tab at the top of this page.

Image source, PA Media

We're going to take a break from our text updates for now, but we will return at about 19:00 BST for Sunday's evening session at the Crucible Theatre.

Judd Trump and Si Jiahui take 5-3 leads into the second sessions of their matches against Shaun Murphy and Ben Woollaston respectively.

Steve Davis
Six-time world champion on BBC Two

On reaching the quarter-finals aged 52 in 2010: "It was a fantastic buzz, I maybe ran out of belief. Another mountain too hard to climb."

On the Class of '92: "Hopefully they don't (run out of belief). They are much more in touch with the top part of the game than I was.

"If one of those three players was to win the World Championship, and maybe beat a young whippersnapper in the final, what an achievement that would be. Maybe their best achievement here."