Mark Allen began the defence of his Northern Ireland Open title with a comfortable 4-0 victory against Ben Mertens at the Waterfront Hall.
While it was not his best performance, Allen recovered from a nervy first frame to defeat the Belgian and make it through the first round.
Allen is aiming to win the Alex Higgins Trophy for a third successive year.
World number three Judd Trump is also through to the second round after beating Jenson Kendrick.
Allen will play Estonian Andres Petrov in the second round, and the 37-year old has now won 14 matches in a row in the Northern Ireland Open.
The Antrim player, who in the build-up to the tournament said the World Snooker Tour schedule was “very restrictive” for players, beat Zhou Yuelong 9-4 in the final of last year’s NI Open.
Trump joins Allen in the second round of this year’s tournament after defeating Kendrick 4-1 earlier on Sunday.
The world number three, who has lifted the English and Wuhan Open this year, is aiming to win three straight ranking titles.
He lost the opening frame against Kendrick before responding well to clinch a 15th straight victory as he seeks his first NI Open win since 2020.
Also through to the last 64 are Neil Robertson after a 4-1 victory over Wu Yize and 2017 winner Mark Williams, who beat Tian Pengfei by the same scoreline.
Shaun Murphy beat Ryan Thomerson 4-2 while wildcard entry Robbie McGuigan, who is from Antrim, won 4-1 against Muhammad Asif.
Gary Wilson narrowly defeat Louis Heathcote 4-3 while David Gilbert overcame Joel Connolly 4-1 in the evening session.
