Jack Lisowski has secured his place in the second round of the Northern Ireland Open with a decisive 4-1 triumph over Chinese player Huang Jiahao at Belfast's Waterfront Hall.
The reigning champion, who claimed his first ranking title at this event last year, took control early to establish a three-frame advantage before closing out the match.
Despite Lisowski's progress, significant upsets occurred on the opening day of the tournament, with two former world champions failing to advance past the first round.
Mark Selby, the four-time world champion and world number five, was defeated 4-2 by Englishman Louis Heathcote in a contest that saw him lead 2-0 before dropping four consecutive frames.
Selby had hoped to become the first player to secure victories across all four Home Nations tournaments, but his campaign ended after allowing Jiahao to narrow the score to 3-1.
Heathcote eventually clinched the fifth frame on the black to send Selby home, meaning he will not face Scotland's Anthony McGill in round two as originally anticipated.
Other notable results included Xiao Guodong losing a final-frame decider to England's Sam Craigie and Cork's Aaron Hill being beaten 4-2 by Thailand's Thepchaiya Un-Nooh.
Former world champions Neil Robertson and Shaun Murphy also suffered first-round losses, with the former falling to Ricky Walden and the latter to twenty-year-old Welsh prospect Liam Davies.
Walden secured a 4-1 victory against Robertson, while Davies capped his performance with a century break of 104 in his win over Murphy.
The tournament continues with further matches scheduled for later in the day at the venue.
Lisowski will now face Scotland's Anthony McGill, who recently defeated Stephen Maguire 4-1 to reach this stage.
No official body has confirmed future outcomes beyond the results reported from the opening session.
This report is based on verified match data and player statements available up to the time of publication.