Bingham won the last three frames of the session
Ronnie O’Sullivan went 5-3 behind Stuart Bingham in the first session of their Betfred World Championship quarter-final clash, while Neil Robertson trails Barry Hawkins by the same scoreline.
O’Sullivan and Robertson both dominated their first two matches, but they face uphill battles to get through to the last four at the Crucible.
Five-time champion O’Sullivan beat Bingham 6-0 the last time they met, in the World Grand Prix semi-finals, and started strongly this time with a break of 116 in the opening frame.
Bingham, who has never reached the semi-finals in Sheffield, hit back to take the next two frames with runs of 64 and 75. Another century from O’Sullivan, 118, made it 2-2, then an 87 in frame five saw him regain the lead.
But it was world number ten Bingham who finished the session strongly, winning three frames in a row with a top run of 56. They resume tomorrow at 2.30pm, with the concluding session at 7pm. First to 13 frames goes into the semis to meet Judd Trump or Ding Junhui.
Hawkins, who was runner-up here in 2013 and a semi-finalist last year, took a 35-minute opening frame today on the colours, then 2010 champion Robertson responded with breaks of 115 and 70 in winning three in a row.
But the Australian failed to score a single point after the interval as world number five Hawkins reeled off four frames on the spin with top runs of 98 and 96.
They return at 10am and 7pm tomorrow, with the winner to meet Shaun Murphy or Anthony McGill.
Hawkins is aiming to reach his third consecutive Crucible semi-final