Defending champion Mark Selby looks comfortably placed to reach the quarter-finals of this year's World Championships needing just three frames on Monday to see off Chinese opponent Xiao Guodong.
The 33-year-old Englishman leads Xiao 10-6 after Sunday's second session which saw them share the eight frames on offer with the Chinese cueman landing the final two blows of the session.
For Xiao it was a markedly better display than the first session where he was outplayed and trailed 6-2.
The winner will play either Australia's former world champion Neil Robertson or Hong Kong veteran Marco Fu, who were embroiled in an engrossing battle.
Neither would yield an inch -- like the first session, where Fu looking all at sea at 4-1 down, had suddenly crackled into life to win three frames in a row including a break of 118 -- and shared the opening two frames of the evening.
Robertson, who revealed last week his form had suffered in past years because of an addiction to computer games, edged back in front to lead 8-7 but 39-year-old Fu took the final one to send them to bed tied at 8-8.
Giantkiller Rory McLeod's progress came to an abrupt end as the conqueror of championship favourite Judd Trump was given a salutary lesson with a 13-3 humbling by Stephen Maguire.
Maguire, who will be making his first appearance in the last eight since 2012, will play the winner of the second round clash between Graeme Dott and Barry Hawkins.
Hawkins looked to have been energised by his 38th birthday in taking a 9-3 lead but the champagne was put on ice as the ever resilient Dott took three consecutive frames.
Hawkins won the last frame of the evening to lead 10-6 heading to the final session.