Jeremy Lawlor and Jacques Snyman both scored half centuries as Carrickfergus chased 143 to beat defending champions Warngstown in their rearranged match at The Lawn.
Needing 12 off seven balls, Alex Haggan struck what was a decisive blow from the first ball he faced, hitting Jamie Gibson over the ropes.
Although it was a case of six and out for Haggan, Ireland A international Lawlor held his nerve, getting the runs required, a two from the fifth ball tieing the match, and a single then winning it.
Lawlor's unbeaten 52 included four boundaries, earlier adding 66 for the second wicket with Jacques Snyman, who top scored with 54 from just 36 balls (4 fours, 3 sixes).
Jamie Gibson of Waringstown
Earlier, Waringstown recovered from 16 for 3, thanks to a fourth wicket stand firstly between Greg Thompson (34) and Lee Nelson (29).
The real acceleration though came from Morgan Topping who cleared the ropes three times in a hard-hit 51 from 34 balls - the home side ending on 142 for 6.
Carrick join Waringstown on eight points, one win behind North Down, Lisburn and CIYMS.
PREMIER LEAGUE RESULT
Waringstown (0) lost to Carrickfergus (4) by 5 wickets
Waringstown 142-6 (20.0 overs, M Topping 51, G Thompson 34, L Nelson 29, M Armstrong 2-19, A Shetty 2-24)
Carrickfergus 143-5 (20.0 overs, J Snyman 54, J Lawlor 52*, G Thompson 2-23)