Pembroke went top thanks to a comprehensive 9-wicket win over The Hills.
The home side had started brightly with an opening stand of 52 between Abbi Harrison 29 (5 fours) and Tahlia Dunne (20), but lost their way to be 111 all out - two wickets for Sarah Forbes.
The reply was dominated by Louise Little, who crunched 8 fours and 2 sixes in an unbeaten 41-ball 64, adding an unbroken 82 for the second wicket with Isobel Jennings (21*).
Phoenix threw a spanner in Merrion's title ambitions with a 64-run win in the park.
Siuin Woods hit seven fours in a 36-ball 48, sharing an opening stand of 61 in eight overs with Alice Tector (25).
Wickets started to fall, and it was a steady 27 from Zara Craig that got Phoenix up to 129 for 7 - two wickets for Aoife Brennan and four run outs.
The Merrion reply was soon in tatters as Georgina Dempsey took three wickets, while Bella Armstrong was run out as they slumped to 20 for 5. Isabel Light made 23 as they attempted to rally, but more run outs saw Merrion 65 all out.
Sophie MacMahon was another Irish player who had a point to prove after being left out of the European Qualifying Squad.
The Leinster all-rounder certainly did that as she brutally dismantled the Malahide bowling hitting 13 of the 27 balls she faced to the boundary, dominating an opening stand with 59 of the 70 runs scored, before falling just after the powerplay.
Rebecca Rolfe made a run-a-ball 48 not out, adding 60 for the second wicket with Joanne Loughran (32) in a Leinster total of 167 for 3.
Malahide's reply never got going - Anna Kerrison (36) top-scoring as they made 109 for 5.
There were three half centuries in a high-scoring game at Jack Harper Park, with Balbriggan beating Rush by nine wickets.
Ocean Bartlett made a run-a-ball 52, sharing a century stand with Lisburn teenager Rebecca Lowe, who hit ten boundaries in an unbeaten 66 as Rush posted 146 for 3.
South African Madison Landsman made short work of the chase hitting 12 fours and a maximum in a 51-ball 84 not out, adding 116 for the second wicket with Lara Maritz (29*) as they clinched the win in the 17th over.