Defending champion Shaun Murphy was dumped out of the Masters in the first round by Mark Allen at Alexandra Palace.
Murphy, who beat Neil Robertson in the final last year, fought back from 5-2 to 5-4 but both men made errors in a scrappy 10th frame that eventually went the way of Allen as he secured a 6-4 victory.
After the first two frames were shared, Allen moved ahead with a break of 137 in the third and then made it 4-2 when Murphy forfeited the frame following three misses.
Another century of 104 put Allen one frame away and, although Murphy managed a break of 100 in the ninth frame, he could not complete the comeback.
Allen will face either Barry Hawkins or Joe Perry in the quarter-finals.