John Anderson's century ensured Merrion remained on course to clinch the Premier title after a 167-run win against Phoenix.
The veritable run machine hit 103, and Jack Carty 70 as Merrion made 235.
Poonish Mehta then ripped the heart out of the fragile Phoenix batting line-up, taking 6 for 8 as they were skittled for 68, losing their last nine weeks for 28 runs.
They now have a 37-point lead over nearest challenger Clontarf who have a game in hand.
North County's faint title hopes evaporated in a low scoring encounter at Sydney Parade against Pembroke.
Two wickets apiece for Jack Balbirnie, Fiachra Tucker, Alex Ridley and JJ Garth saw County dismissed for 101 - Adam Coughlan making 33 and Jonno Andrews 23.
It looked as if it would be enough as Eddie Richardson and Malcolm Nofal reduced them to 63 for 8, but an unbroken 9th wicket stand of 40 between Paul Lawson (29*) and Gavin Hoey (15*) got Pembroke over the line.
The Hills prevailed in another low scoring contest at Milverton, edging out Leinster by 50 runs.
Albert van der Merwe hit 5 fours and 3 sixes as he top scored with 57, adding 90 for the second wicket with keeper Mark Donegan (37).
Nic Pretorius added 24, but his dismissal saw six wickets fall for seven runs, all out for 164.
Gareth Delany and Andrew Clough taking three wickets, and Joe Carroll two.
Max Sorensen (5-26) and Naz Shaukat (3-13) blew away the Leinster top order as theyw ere reeling on 16 for 5.
Joe Carroll (59) and Saqib Bahadur (35) added 81 to bring Leinster back into contention, but a late order collapse saw them all out for 114.
In Division Two, Malahide were crowned champions as they beat Rush by five wickets.
Player of the Year in the division Matt Ford hit an unbeaten 65, and Anish Desai 52 as they chased 158.
Kenny Carroll's 76 trumped Kenny McDonald's 73 as Railway moved into the play-off slot by beating basement side Terenure by 43 runs.
Rush's re-arranged fixture with Cork County was washed out on Friday.