O'Sullivan had to fight back in the morning session against Ding, who started extremely well, and it was the same for most of the evening session except he failed to produce the comeback.
Ding took six of the eight evening frames to open a lead going into the final session and O'Sullivan faces a fight on his hands to make it to the semi-finals.
Where as 'The Rocket' looked rusty and made some basic mistakes and missed easy pots, Ding looked calm and collected, and was ready to punish any mistakes from his opponent.
On the other table Higgins is in an even better situation as he is just two frames away from victory against Wilson.
Like Ding Higgins took six of the frames on offer which included two centuries of 129 and 125 and the four-times champion looks a good bet to reach the semi-finals, where he will face either Barry Hawkins or Stephen Maguire.
Ronnie O'Sullivan 6-10 Ding Junhui (Best of 25)
0-79 (71), 12-128 (128), 7-77 (71), 79-11 (63), 99-0, 102-16 (65), 69-76, 19-107 (59), 40-87 (63), 84-42 (84), 31-64 (64), 56-82 (65), 0-120 (120), 35-68 (59), 0-87 (56), 104-0 (104)
Kyren Wilson 5-11 John Higgins (Best of 25)
1-72, 5-94 (60), 67-31, 92-0 (92), 36-53, 62-15 (61), 17-63 (62), 9-67 (59), 0-129 (129), 67-45, 86-42, 0-74 (74), 0-135 (135), 97-0 (97), 45-71, 4-71
Defending champion Mark Selby has taken an early lead in his quarter-final against Marco Fu as he ended with a 6-2 lead after the first session.
Fu looked horrendously out of sorts, missing a number of simple pots and making other basic mistakes, as Selby took the first five frames.
Fu offered a bit of a fight-back, winning two of the last three frames, but he faces a tough fight in the second session.
On the other table Stephen Maguire battled back from 5-1 down to trail 5-3 against Barry Hawkins which included a dramatic battle in the seventh to win his second frame.
Interestingly none of the four players made a century in this session.
Read the full article on eurosport.co.uk: Ding leads out-of-sorts O'Sullivan, Higgins takes control against Wilson