Three-time world champion Mark Selby will take a 5-4 lead into the second session of his World Championship first-round match with Jordan Brown.
Both players struggled to find consistency in Monday’s first session at Sheffield but Selby edged the final frame to secure a narrow advantage.
Northern Ireland’s Brown, making his Crucible debut, had a best break of 76 in the second frame.
Selby’s best run saw him compile a 119 in frame seven.
A scrappy opening frame set the tone for the session, Selby emerging triumphant after 39 minutes to take an early lead.
Brown, ranked 73 in the world, took the next two frames, but Selby responded by winning the fourth to level at the mid-session interval.
The Antrim player moved ahead again but a 50 break in the sixth, followed by a century in the next, saw Selby go one clear.
The standard again struggled to rise above the mediocre as Brown levelled at 4-4, before Selby grabbed a lengthy ninth frame.
World number seven Selby, 37, has won the English and Scottish Opens this season, but has lost in the second and first rounds of the World Championship in the last two years.
The second session will take place on Tuesday afternoon, with the winner facing either Shaun Murphy or Noppon Saengkham in the round two.