Ronnie O'Sullivan took command of his World Championship semi-final against John Higgins as Mark Williams set up a thrilling finale to his Crucible clash with Judd Trump.

O’Sullivan made breaks of 99, 91, 70 and 73 to open up a 10-6 lead, but it was the manner in which he won the last frame of the session on a respotted black which will have hurt Higgins the most.

Higgins looked set to limit the damage – and make his highest break of the match into the bargain – only to miss a black off the spot which would have left O’Sullivan needing a snooker.

The six-time champion produced a stunning positional shot to get on the black from the penultimate red and a 43 clearance levelled the scores at 58-58.

O’Sullivan’s attempt to double the respotted black left Higgins with a difficult pot into the green pocket which the 46-year-old Scot was unable to convert, the black running down the table to leave O’Sullivan a simple pot into the middle.

Higgins had earlier taken two of the first three frames of the day to lead 6-5, but O’Sullivan kicked off a winning run of five frames in a row with a break of 99, despite having to ask referee Marcel Eckardt to remind spectators in the front few rows to sit still.

In the other semi-final, three-time champion Williams staged a brilliant fightback to trail 2019 winner Trump 13-11 heading into their final session on Saturday afternoon.

Trump led 11-5 after the second session and began Friday evening’s action with a break of 120, only for Williams to come storming back into the contest.

The Welshman kickstarted a run of five frames in succession with a total clearance of 137 and added contributions of 58, 53, 57 and 77 to close the gap to 12-10.

Trump, who had not potted a single ball in four of the last five frames, responded superbly with his second century of the session, but Williams took the final frame of the night to leave the outcome firmly in the balance.