YMCA's probable swansong at Claremont Road turned into a real celebration as they went out with a bang producing a near faultless display to sweep aside Malahide by 117 runs and clinch the Premier title for the seventh time.
Batting first there was a slight wobble at 94 for 6, but a 7th wicket stand of 97 between top scorer Adam Rosslee - who hit 12 boundaries in his 85 - and Jamie Forbes (48) took them to 239 for 9.
Malahide's top order was blew away by Mikey O'Reilly (5-18) to slump to 27 for 6, and there was no way back from that.
Mike Frost hit 6 fours in his 55, adding 57 with Andrew Sheridan (30), but it was only delaying the inevitable - skipper Tim Tector taking two wickets on his way to lifting the trophy.
Railway Union produced the first half of the 'Great Escape' crushing Leinster's title hopes with a five-wicket win at Park Avenue.
Monil Patel (33) and Joey Carroll (23) took Leinster to a steady 54 for 2, but they couldn't kick on as four wickets for Hamza Maan, and two apiece for Liam McCarthy and Brandon Kruger saw them bowled out for 117.
Gareth Delany took three wickets in the chase, but Brandon Kruger hit three sixes in his 33, and Kenny Carroll made 27 in a vital win.
Part two comes next Saturday with an all or nothing clash with Phoenix to determine who gets the last Premiership slot.
A dramatic collapse by The Hills saw them fall through the relegation trap-door as they lost by nine runs at home to Merrion.
There appeared no danger as they reached 140 for 2 thanks to a third wicket stand of 85 between Mark Donegan (24) and Nicolaj Laegsgaard.
The Dane had smashed 91 from only 47 balls (11 fours, 5 sixes), but his dismissal put the Milverton side in a tailspin as pressure told, and they lost eight wickets for 40 runs to be 180 all out.
Earlier, John Anderson's 83 (4 fours, 2 sixes) had held the Merrion innings together after an opening stand of 59 between Stephen Doheny (31) and Jack Carty (19).
Balbriggan finished the season on a high as they beat Clontarf by five wickets at Jack Harper Park.
Clontarf posted 213 as they lost their way after an opening stand of 72 in nine overs between skipper Eoghan Delany (35) and Ryan Karunakaran (28). It took Bobbo Forrest's 36 to get them over the 200. Farooq Nasr claimed three wickets, while there were two apiece for Kashif Ali, Andy Darroch and Chris De Freitas.
The result was never in doubt thanks to a third wicket stand of 129 between top-scorer Cameron Rowe - who hit 9 fours and 2 sixes in his 79 - and Chris De Freitas who made 57 (7 fours, 1 six). Captain Greg Ford thumped seven boundaries in a rapid unbeaten 37 to clinch the win in the 36th over.