On Saturday morning, champion Stuart Bingham reeled off five frames in a row to turn a 3-1 deficit into a 6-3 lead over David Gilbert, in a match that is set to resume on Sunday.
The afternoon session saw Neil Robertson begin his bid for a second world title by taking a 6-3 lead over Wu Yize.
Robertson's 138 break in frame two helped him towards a 4-1 lead before Wu produced back-to-back breaks of 107 to keep his head above water.
Pegged back to 4-3, Robertson took the final two frames to swat aside hints of a comeback.
Like Robertson, Luca Brecel pulled away from Ricky Walden as their first session came to a close to lead 6-3, while Ali Carter finds himself trailing Jak Jones 5-4.
SATURDAY APRIL 15
Morning Session (10am)
First Round (Best of 19 frames)
TV Coverage: Eurosport & BBC
Afternoon Session (2.30pm)
First Round (Best of 19 frames)
TV Coverage: Eurosport & BBC
Evening Session (7pm)
First Round (Best of 19 frames)
TV Coverage: Eurosport & BBC
SUNDAY APRIL 16
Morning Session (10am)
First Round (Best of 19 frames)
TV Coverage: Eurosport & BBC
Afternoon Session (2.30pm)
First Round (Best of 19 frames)
TV Coverage: Eurosport & BBC
Evening Session (7pm)
First Round (Best of 19 frames)
TV Coverage: Eurosport & BBC