Irish internationals Lorcan Tucker and Harry Tector powered Pembroke to a whopping 189-run win at Phoenix.
The pair shared a third wicket stand of 112 with Harry's 74 coming from 68 balls including 8 fours and 2 sixes.
It was Tucker though who provided the match defining innings, hitting 10 fours and 7 sixes in his unbeaten 139 from 121 balls.
Gavin Hoey hit three sixes in a whirlwind 25 as his side racked up 320 for 9.
Phoenix's trio of Irish internationals shared the wickets with three for Tyrone Kane and George Dockrell, while Ben White took two.
Dockrell's 52 was the best of a chase that never materialised - all out for 131.
Gavin Hoey picked up 3-29, while there were two apiece for Fiachra Tucker, Barry McCarthy and Harry Tector in the statement win.
Balbriggan powered to a 9-wickets win at Malahide with Cameron Rowe the hero with a century.
Chasing a modest 162, Rowe hit 17 boundaries in his unbeaten 103 from 105 balls, sharing stands of 75 for the first wicket with Ghanim Dhara (23) and an unbroken 90 in 13 overs for the second with Chris DeFreitas (26*).
Malahide's 161 saw teenager Adam Doyle make a solid 50 opening, with their total boosted by 46 extras.
Dylan Lues was the bowling star, claiming six wickets for just 16, while Sam Willemse picked up a brace as the 2022 champions showed their intent with a statement win.
Matthew Vercoe-Curtis enjoyed a productive debut as he made a century to help Leinster win the game of the day as they beat Merrion by 16 runs at Anglesea Road.
He top-scored with 105 (9 fours, 6 sixes), sharing a second wicket stand of 191 in 29 overs with Monil Patil, whose 73 included 8 fours and 2 sixes.
There were breezy cameos too for Gareth Delany (39) and Saqib Bahadur (31*) in a final total of 301 for 6 - three wickets for Swapnil Modgill and two for Mikey O'Reilly on debut.
The chase was an entertaining one as the hosts threatened to overhaul their tough target.
They looked on course after an opening stand of 155 in 23 overs between Modgill (84) and Mick Lewis (75), but Leinster held their nerve and kept getting wickets as the required rate climbed.
Joey Carroll (4-45), skipper Bilal Azhar (3-40), and Luke Callanan (2-59) doing the damage.