Reigning champion Kyren Wilson holds a 6-3 lead over Lei Peifan in the first match of his world title defence at the Crucible Theatre in Sheffield.
The world number two twice missed blacks off the spot in the second frame as Crucible debutant Lei, 21, went 2-0 in front.
The 33-year-old Englishman recovered to win the next six frames in succession, making a 136 break in the eighth to add to three earlier half-centuries.
But Chinese qualifier Lei pinched the final frame of the session, after Wilson missed a pink trying to get position on a tricky last red, to give himself hope of a comeback.
Their best-of-19-frames contest will be played to a finish from 19:00 BST.
