Defending champion Ronnie O'Sullivan holds a 9-7 lead over Ali Carter in their World Championship last-16 match at the Crucible.

O'Sullivan led 5-3 after Saturday's opening session and a break of 86 saw him extend that advantage to 6-3.

But Carter won four of the next five frames to make it 7-7, before O'Sullivan took the last two frames.

Meanwhile, Ding Junhui recovered from 6-2 down to lead 9-7 against Mark King.

Ricky Walden needs three more frames to beat Robert Milkins and move into the World Championship quarter-finals.

World number 13 Walden led 5-3 after the first session and extended his lead to 10-6 before Monday's final session.

Premier League champion Stuart Bingham and Mark Davis are level at 8-8 in another last-16 match.

Ricky Walden (Eng) 10-6 Robert Milkins (Eng)

72-59 (60), 65-1, 86-32 (76), 4-106 (106), 71-35, 51-67, 67-16, 2-117 (104), 54-13, 75-14, 72-13 (63), 76-25 (76), 23-59, 60-65 (Walden 50), 4-102 (77), 66-29 (51)

Mark Davis (Eng) 8-8 Stuart Bingham (Eng)

36-78, 79-40, 17-73 (67), 69-17 (57), 4-115 (106), 63-55, 1-96 (82), 84-3 (84), 0-68 (54), 62-31, 19-92, 38-70, 71-22, 75-0 (75), 59-37, 6-87

14:30 BST

Ronnie O'Sullivan (Eng) 9-7 Ali Carter (Eng)

66-18, 83-8 (78), 76-15 (66), 21-92 (53), 56-16, 125-0 (125) 0-82 (82), 26-84 (51), 86-0 (86), 0-121 (73), 12-87 (87), 105-13 (105), 61-64 (O'Sullivan 61, Carter 63), 18-63, 73-11 (73), 86-0 (86)

Ding Junhui (Chn) 9-7 Mark King (Eng)

57-66 (53), 51-63 (59), 24-76 (52), 107-4 (107), 114-1 (114), 11-79 (57), 5-66, 2-62 (53), 81-19 (59), 0-98 (98), 74-4 (74), 76-24, 73-15, 0-90 (63), 103-0 (103)