Three-time Masters champion Mark Selby suffered a surprise defeat to Ali Carter in the first round of the 2020 tournament in London.
Ali Carter was a replacement for Ronnie O'Sullivan, who chose not to play in the tournament, and led 3-1 before falling 4-3 behind.
But he won three frames in a row to claim a 6-4 victory to eliminate three-time champion Selby.
Earlier, Ding Junhui suffered a 6-3 defeat by Joe Perry.
The Chinese player arrived in fine form having won theUK Championshipin York last month, but despite a 135 break in frame two, he was never ahead.
Englishman Perry, the world number 16 who reached the final of this event in 2017, was too consistent and breaks of 71, 93 and 83 secured victory.
Read the full report from those matches here.