|Venue:Crucible Theatre, SheffieldDates:31 July-16 August|
|Coverage:Watch live on BBC One, BBC Two, BBC Four and Red Button, with uninterrupted coverage on BBC iPlayer, BBC Sport website and BBC Sport app.Full details and times.|
Ronnie O’Sullivan trails Mark Williams 6-2 at the end of the first session of their World Championship quarter-final.
A high-scoring start saw the former champions trade frames with breaks of 70 and 101 before the Englishman went 2-1 up.
However, Wales’ three-time winner Williams took control with a vintage display that included breaks of 56, 72 and 130 as he won five frames in a row.
Earlier, Kyren Wilson took a 5-3 lead over defending champion Judd Trump.
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World number one Trump knocked in breaks of 85 and 76 against the 2018 Masters runner-up.
But Wilson reeled off three consecutive frames to build a 4-2 lead before the players traded the final two frames of the session.
Trump, who is yet to hit top form, has now trailed at the end of the first session in all of his three matches at the tournament.
Mark Selby holds the upper hand in his quarter-final with Neil Robertson after building a 5-3 lead over the Australian.
Selby edged a marathon 58-minute opening frame, the longest in this year’s tournament, to take the lead and then reeled off the next four frames as well to establish a 5-0 advantage.
However, Robertson hauled himself back into the match by winning the final three frames of the session, recording breaks of 83, 66 and 65.
Scotland’s Anthony McGill established a commanding 7-1 lead over Norway’s Kurt Maflin in the final last-eight tie.
McGill had moved into the quarter-finals after staging a remarkable comeback to beat fellow qualifier Jamie Clarke 13-12 in abad-temperedencounter.