Fourth seed Ding dominated the first three frames, making breaks of 111 and 58, but Day responded with breaks of 79, 125 and 105 as he levelled things up.

Day was skilful in the seventh frame, snookering his opponent and taking the lead. Ding tried to hit back immediately, breaking with 62 before accidentally touching the blue when he was using the rest, which allowed Day back in to clear.

Ding won the next frame but Day took the last in style with a break of 115, the fifth century of the match.

It was the Welshman's first ever match at Alexandra Palace, and he has not competed at the Masters since 2010.

Day now faces either John Higgins or Anthony McGill in the quarter-finals on Friday evening.