The Robinson Services Premier League started with victories for Waringstown, CIYMS, North Down and Carrickfergus.
Game of the day was undoubtedly at The Lawn as Lee Nelson sealed a dramatic three-run win for the Irish Cup holders as they edged out Muckamore, who looked likely to clinch a shock before falling short with the finishing line in sight.
Chasing 233, Ireland Academy's Marcus O' Riordan's 63 helped the Moylena side to 225 for 7, but Les Allen was bowled by Adam Dennison, Sam Gordon run out, and then Neil Gill was trapped lbw by Nelson as Waringstown got off the hook.
Earlier Waringstown had reached 138 for 1 with half centuries for Dennison and Nelson, and 45 from James Hall, before they stumbled to finish on 232 for 9 to give Muckamore a sniff which they almost took.
Ruhan Pretorius hit 107 as North Down chased 232 to beat CSNI by four wickets.
Pretorius hit 14 fours and two sixes as he and Ally Shields (71) added 177 for the fourth wicket after Graeme McCarter (4-37) had reduced them to 28 for 3.
Andre Malan (88) and Marc Ellison (68) had added 105 for the second wicket as they reached 124 for 1 after 24 overs, but the second half of the innings stuttered somewhat and their final total of 231 wasn't enough.
Defending champions CIYMS got off to a winning start at Lisburn, where Obus Pienaar hit an undefeated 101 to dent Lisburn's hopes of a victory on their top flight return.
Pienaar shared a century stand with Nigel Jones (41) as the Belmont side survived a few flutters along the way as Davy Simpson and Faiz Fazal each took three wickets before sealing the four wicket win.
Adam Berry top-scored with 55 as the Wallace Park side posted 196 - Jonathan Waite (44) and David Simpson (41*) also in the runs.
There was another centurion at Carrick where Jacques Snyman made 124 as Carrick racked up 320 at home to Instonians.
Snyman added 194 with Jamie Holmes (65) for the 3rd wicket, while CJ van der Walt hit an unbeaten 40 in an impressive display.
Instonians struggled to 136 for 8 in the reply, but a 9th wicket stand of 111 between Matthew Humphreys (77) and James Metcalfe (42*) gave the result respectability as they finished on 256.
The full scorecards from the Premiership games can be found here: