Mark Williams launched the defence of his Northern Ireland Open title with a 4-2 first-round win against Alfie Burden.
Williams, 43, who beat Yan Bingtao 9-8 in last years's final before going on to claim his third world title later in the season, made two breaks of 91 and another half-century (69), and will now face Ali Carter.
However, Antrim man Mark Allen, a recent ranking event winner at the International Championship in China, went down 4-1 to Niu Zhuang.
Carter cruised through to the second round with a 4-1 win against Paul S Davison, but four-time world champion John Higgins crashed out after a 4-2 defeat to Rory McLeod.
Barry Hawkins, Anthony McGill and Stuart Bingham were also first-round victims, losing 4-3 to Chen Zifan, 4-0 to Alexander Ursenbacher and 4-2 to Peter Lines respectively.
Mark Davis, Luca Brecel, Gerard Greene, Ryan Day, Gary Wilson and Lee Walker were among those who progressed.
Today, Fergal O'Brien is in action against David Gilbert and Ken Doherty will face Scott Donaldson.
