Former world champion Shaun Murphy cruised to a commanding 7-2 lead after the first session of his first-round match against Crucible debutant Daniel Wells.
In a high-quality session, 42-year-old Murphy – aiming to win a second world title 20 years after his first success – won four frames in a row to take control.
He needs to win only three more frames when the match resumes on Wednesday morning (10:00 BST).
Murphy won the Masters in January and is looking to become the first player since Judd Trump in 2018-19 to win that tournament and the World Championship in the same season.
He made a fine start with a break of 64 but Welshman Wells, who had to battle through three qualifying rounds to secure his place at the annual 17-day event, showed his break-building ability with a clearance of 131.
But Murphy made breaks of 63, 100, 57 and 138 to move into a dominant 5-1 advantage.
Wells, 36, made his second century with 109 in frame seven, only for Murphy to instantly restore his four-frame lead with a run of 76.
A missed black off the spot cost Wells the chance to reduce his arrears in the final frame of the session, with Murphy taking advantage with a break of 89.
World number one Judd Trump also began his campaign on Tuesday and holds a 6-3 lead against China’s Zhou Yuelong in a match that concludes on Wednesday night (19:30 BST).
Breaks of 93, 61, 117 and 62 helped Trump to a 5-1 lead before Zhou, 32nd in the world, edged a scrappy seventh frame, which lasted more than 40 minutes.
The pair shared the last two frames to leave Trump needing four frames on Wednesday.
