Chinese number one Ding Junhui led compatriot Liang Wenbo 9-7 after the second session in the second round of the World Snooker Championship on Friday.
Ding, last year's runner-up, built a 6-2 advantage in the first session, but Liang, this year's England Open winner, managed to narrow the gap to just two frames.
Liang won the first two frames of the night session with breaks of 84 and 75 to close to 6-4. A high quality contest saw Ding hit back with 91 before Liang made a 130, missing the final pink when he looked set for a 143.
Ding came from 51-0 down to win frame 13 and go 8-5 up, then Liang made a 79 to take the next. Ding's 94 made it 9-6 and he had first chance in the final frame of the session but missed the green to a baulk corner on 27 and his opponent hit back with 36 and 39 to narrow his overnight deficit.
Elsewhere, rising star Kyren Wilson reached the quarterfinals for the second consecutive year with a 13-10 defeat of former world champion Stuart Bingham.
The 25-year-old Wilson became the first man into the last eight and will now face John Higgins or Mark Allen.
Wilson, who won his first ranking title at the Shanghai Masters last season, said: "I want to win the tournament, I'm in the quarterfinals and I've got to win three more matches to lift that trophy. That's the main goal, that's what I've dreamt of since I was a little boy."