Second-round matches are best of 25 frames
RESULT: John Higgins 13-12 Xiao Guodong
RESULT: Mark Williams 13-10 Hossein Vafaei
END OF SESSION: Luca Brecel 7-1 Ding Junhui - resumes on Sunday
END OF SESSION: Ronnie O'Sullivan 6-2 Pang Junxu - resumes on Sunday
END OF SESSION: Lei Peifan 6-10 Zhao Xintong - resumes on Sunday
END OF SESSION: Si Jiahui 5-3 Ben Woollaston - resumes on Sunday
Brecel 0-1 Ding
Ding Junhui with a quite impressive start to his last-16 match with Luca Brecel.
The Chinese player begins with a beautifully-crafted break of 141 as he clears the table in style, sealing it by powerfully slamming the black into the pocket.
Ding looks like a man on a mission here.
Image source, BBC SportChris Wakelin and Mark Williams are both through to the quarter-finals. At least one more player will be joining them this evening.
Si v Woollaston
Image source, Getty ImagesBen Woollaston shot into the snooker spotlight with his surprising first-round win against Mark Selby at the World Championship, which secured a meeting with Si Jiahui.
A first win at the famous Crucible Theatre has been a long time coming for Woollaston, who is now 37.
But if the surname rings a bell, then that might not be entirely down to Ben's snooker achievements alone. Wife Tatiana is one of the sport's leading referees.
Brecel v Ding
John Parrott
1991 world champion on BBC Two
Image source, PA MediaHe's unbelievable. I love watching him and we're going to see some more "Luca snooker". You don't know what you're going to get with him but he's a breath of fresh air on this circuit.
Brecel v Ding
According to BBC presenter Hazel Irvine, Luca Brecel was still in Belgium this afternoon. He travelled by jet to the UK and arrived at the Crucible Theatre in Sheffield at about 18:35 - 25 minutes or so before the first session of his match with Ding Junhui was scheduled to start.
BBC Two
Coverage is under way on BBC Two and will switch to BBC Four at 20:05 BST.
You can watch the action uninterrupted on the BBC iPlayer and on this page by clicking on the "Watch and listen" tab.
As you may have noticed in the schedule in our previous post, the match between John Higgins and Xiao Guodong ran over time this morning so it will be completed once a table becomes available.
The winner will play Mark Williams in the last eight.
All times BST, matches best of 25 frames
10:00
14:30
19:00
We're going to take a little break and we will be back with you for two more second-round matches from 19:00 BST...
Result: Williams 13-10 Vafaei
Michael Emons
BBC Sport at the Crucible Theatre
Mark Williams turned 50 in March and is the oldest player to reach the last eight at the Crucible since six-time winner Steve Davis did so in 2010 at the age of 52.
Williams held a 9-7 advantage after the second session on Friday and he took two of the first three frames on Saturday.
Qualifier Vafaei made breaks of 74 and 72 to pull it back to 11-10 in favour of Williams, who won the next two frames - including a stylish 115 break in frame 23 - to seal the victory.
Result: Williams 13-10 Vafaei
Ken Doherty
1997 world champion on BBC iPlayer
It's been a great performance by Mark Williams.
He's been put to the test, Hossein never went away and pushed him, but it's the former champion, with all his guile and experience, that is going through to the quarter-finals.
Williams 13-10 Vafaei
Image source, Getty ImagesMark Williams is the second player through to this year's World Championship quarter-finals.
He completes a 13-10 win over Hossein Vafaei with a break of 115 - his second century of the match.
Williams - the champion in 2000, 2003 and 2018 - joins qualifier Chris Wakelin in the quarter-final line-up and will play either John Higgins or Xiao Guodong in the last eight.
Williams 12-10 Vafaei
A missed red with the rest by Hossein Vafaei gives Mark Williams his first real chance to wrap up frame and match. He'd give anything for a break of 60 or 70 to get over the line here.
Has Vafaei played his last shot in this year's World Championship?
Williams 12-10 Vafaei
No balls potted yet at the start of the 23rd frame but Mark Williams has a 12-point lead thanks to three Hossein Vafaei fouls.
There are plenty of loose reds available for whoever can pot the first ball.
Williams 12-10 Vafaei
Hossein Vafaei pots a couple of reds and colours, but Mark Williams knocks in a long red to put the frame to bed.
He needs just one more frame to set up a quarter-final with either John Higgins or Xiao Guodong - who will return later tonight to complete their second-round match after running over time this morning.
Vafaei needs all three remaining frames if he is to reach the last eight.
O'Sullivan 6-2 Pang
Michael Emons
BBC Sport at the Crucible Theatre
Ronnie O'Sullivan holds a four-frame lead against China's Pang Junxu after dominating the first session of their last-16 tie.
O'Sullivan, 49, is aiming to become the first man in the modern era to win the event eight times and he remains on course to do so after he pounced on repeated mistakes from qualifier Pang, ranked 27th in the world.
The match resumes at 14:30 BST on Sunday with O'Sullivan 6-2 ahead and he could win with a session to spare, if he claims seven of the eight scheduled frames.
O'Sullivan had won the last five frames in his 10-4 success over Ali Carter in round one and raced into a 4-0 lead against Pang, aided by breaks of 58, 91, 50 and 63.
Pang made a 119 century in frame five, but that was his only run above 50. He had a chance to end only two frames behind but another missed pot in frame eight helped O'Sullivan move closer to the winning target of 13.
O'Sullivan 6-2 Pang
Dennis Taylor
1985 world champion on BBC iPlayer
It's been a good afternoon for Ronnie O'Sullivan. Pang Junxu is not out of it but he has a bit of a mountain to climb against a player of the Rocket's quality.
Williams 11-10 Vafaei
Image source, PA MediaSnooker is a game of fractions and that comes to pass in frame 22 as Mark Williams moves to the brink of a two-frame lead again.
Hossein Vafaei hits a long red sweetly towards the top corner but it rattles in the jaws and comes out. Any slower and it probably would have dropped.
Williams powers in a tricky red to the corner with his next shot and gets himself a 60-point lead with only 59 remaining.
However, Williams misses a black to the corner that would have made it absolutely safe and Vafaei returns to the table needing one snooker.
O'Sullivan 6-2 Pang
Eventually Ronnie O'Sullivan manages to pot both the remaining reds and then works his way through the colours. Poor positioning after potting the pink leaves O'Sullivan unable to clear up but he's not too fussed.
The Rocket is in a strong position heading into tomorrow's second session - they will resume at 14:30 BST on Sunday.
O'Sullivan 5-2 Pang
Concentration waning a little for both players in a messy final frame of the afternoon session on Table One. Ronnie O'Sullivan has 62 points and is 39 ahead of Pang Junxu with 43 left on the table.
Tactical play from both players around these final two reds.
