Following a re-rack, it took Selt 30 minutes to win a scrappy opening frame and trim Selby’s lead to two frames at 6-4.
But Selby found his form in the second frame of the evening with an impressive break of 71.
Selt had a glimmer of hope midway through the next frame when Selby left a tight red over the pocket. But Selt, who failed with an ambitious attempt to swerve around the black, failed to capitalise and the Jester from Leicester secured the frame at the second time of asking to go 8-4 up.
Another fine frame of cueing and precision positional play by Selby saw him move to within a frame of victory before the mid-session interval and he went on to clinch it 10-4 to set up a meeting with Barry Hawkins.
FIRST SESSION REPORT
World number one Mark Selby will take a 6-3 lead into Wednesday’s deciding session against qualifier Matthew Selt at the World Championship in Sheffield.
Selby looked in command of a scrappy match punctuated by missed pots and long bouts of safety, taking a 5-0 lead despite managing a highest break of just 46.
But Selt, who boasts victories over John Higgins and Stephen Hendry, dug deep to get himself on the board with an accomplished 87 break and also took the next.
Selby halted the run with an outrageous double on the black into the bottom right corner to extend his lead to four frames but Selt gave himself hope of an upset, a 57 break in the final frame helping him stay just about in touch.