Ding Junhui beat Mark Williams 6-5 in the deciding match of the final frame to move into the quarter-finals of the Masters at Alexandra Palace.
While neither player was at their best in a split opener in which the first two frames were shared with a top break of 36, the entertaining contest burst into life after the mid-session interval.
After successfully breaking Williams twice and 57, Williams, the two-time winner, took a 3-2 lead before the momentum returned to his Chinese opponent, who enjoyed runs of 64 and 60.
In a seesaw encounter, Williams compiled a brilliant break from 136 to level and then squeezed the ninth frame after Ding faltered at 66 to take a 5-4 lead.
However, the 2011 champion made a 76 to force 11 after enjoying a fortuitous series of balls, then sealed his victory with a brilliant break of 90 points.
“I had a bit of luck when I was 5-4 down. I smashed all the balls and he didn't get any chance,” Ding told BBC Sport.
“I love the Masters tournaments. They are always difficult. We both struggled at the beginning and I told myself to relax.”
Deng will now face Judd Trump or Barry Hawkins in the quarter-finals, while Mark Selby takes on Ali Carter later on Monday (19:00 GMT).
