Matthew Moffitt picked up three wickets for 19 runs off his four overs, then top-scored for Counties Manukau with an unbeaten 33 from 35 balls.
Opener Sterling Speedy, fresh off the only century of the tournament so far, made a quickfire 31 from 20 before Connor Starck (1-26-4) claimed his prized wicket.
Riker Rolls got 2-18-4, and Fearnley and Caleb Taewa nabbed the other wickets.
Poverty Bay were outclassed by unbeaten Waikato Valley in their round five T20 game.
McGuinness (13 off 14 balls) top-scored as Poverty Bay were rolled for 57 in 13 overs – 23 extras boosting their tally.
Waikato Valley made it five wins from five games for the loss of two wickets
Heading into the last day, Sterling’s century was the score of the tournament, while McInnes and Counties Manukau’s Akaldeep Lahory had scored two half-centuries each over the week.
SCOREBOARD
Round 4, T20
Hamilton 134 all-out in 19.2 overs (Chris Pradeep 30, Noah McConnell 28, Aditya Gulla 26, Angus Spelman 21; Lucas Neill 3-28-3, Lachlan Hogan 2-12-3.2, Jonah Funnell 2-25-4) def Bay of Plenty Lakelands 98 all-out in 19.4 overs (Jai Poonia 30, Aidan Hogg 20; Gulla 3-11-3, Jackson Botherway 2-11-4, Pradeep 2-24-3, Taine Grover 2-21-4) by 36 runs.
Waikato Valley 82-4 in 11 overs (Quintus Daniell 50; Caleb De Bruin 3-11-3) def Northern Districts Maori 80 all-out in 19.2 overs (Riley Parkinson 22; Jackson Brown 3-4-17, Joe Lang 2-7-4, Maccy Maber 2-15-3.2) by six wickets.
Northland 108-7 in 20 overs (Josh Laing 28no, Rafe Fleming-Bone 20, Tommy Litchfield 20; Joseph Carter 3-27-3, Nihar Parmar 2-15-4) def Bay of Plenty Coastlands 104 all-out in 19.4 overs (Ashton Lucas 25no; Laing 3-14-4, Owen Prinsloo 2-24-3) by four runs.
Counties Manukau 128-5 in 18.2 overs (Matthew Moffitt 33no, Chainvir Singh 26, Sterling Speedy 31; Riker Rolls 2-18-4, Connor Starck 1-26-4, Nathaniel Fearnley 1-17-2, Caleb Taewa 1-12-2) def Poverty Bay 127 all-out in 19.5 overs (Patrick McInnes 56, Fearnley 21) by five wickets.
Round 5, T20
Bay of Plenty Coastlands 137-7 in 20 overs (Nihar Parmar 32, Flynn Waller 30no, Harrison Miles 26; Josh Waller 2-13-3; Caleb De Bruin 2-23-4) def ND Māori 92 all-out in 19.4 overs (Matthew Dow 3-3-3; Parmar 3-4-1.4) by 45 runs.
Northland 83-1 in 12.5 overs (Nate Cunis 28no, Rafe Fleming-Bone 27no) def Bay of Plenty Lakelands 82-9 in 20 overs (Jai Poonia 25; Campbell Soanes 2-12-4, Thomas Ward 2-20-4, Dailyn Dickeson 2-24-4) by nine wickets.
Counties Manukau 137-4 in 16.4 overs (Akaldeep Lahory 58no, Oliver Farrell 46, Matthew Moffitt 20; Joshua Weerasinghe 2-41-3.4) def Hamilton 136-3 in 20 overs (Noah McConnell 60, Jackson Botherway 31; Moffitt 3-22-4) by six wickets.
Waikato Valley 58-2 in 11.3 overs (Jacob Hagoort 18, Maccy Maber 16no; Caleb Taewa 1-12-2, Jonah Reynolds 1-19-3) def Poverty Bay 57 all-out in 13 overs (Taye McGuinness 13; Joe Lang 4-21-3, Jackson Brown 2-6-3) by eight wickets.