Mark Selby held on to take a 4-3 lead following the first session of his Dafabet World Snooker Championship quarter-final against Alan McManus in Sheffield.
The 30-year-old from Leicester, who won a battle of former Crucible beaten finalists as he saw off a fightback from Ali Carter to record a 13-9 victory in the last 16, impressed with a century break during the sixth frame to level the match for the second time before claiming the final frame of the session.
McManus earlier fought his way back from two frames down and took the lead with victory in the fifth before Selby won the next two to reclaim his advantage ahead of Tuesday evening.
McManus, who survived a comeback to see off fellow veteran Ken Doherty 13-8 in the last 16, easily lost the first frame before forcing a difficult end to the second where - after a lengthy safety exchange - Selby finally potted the pink to take a 2-0 lead.
But the 43-year-old Scot, once again wearing his tartan trousers at the Crucible, managed to break back into the match with victory in the next two frames to level at 2-2 before claiming the next one to take control for the first time.
The 2007 runner-up Selby, though, hit back with a 110 break and took the sixth frame then edged 4-3 ahead following the seventh before the players were taken off the table one frame early. The match will resume on Tuesday evening.
Barry Hawkins raced to a 4-1 advantage over Dominic Dale in their last-eight clash, eventually taking a comfortable 6-2 lead into the evening action.
Hawkins, who managed to hold off Ricky Walden 13-11 to progress on Saturday, looked like there was no stopping him as he took the first two frames before Dale pulled one back.
The world number four continued to battle on and will be pleased to start the next session with a dominant lead.