At one stage ND were 25-6.
Depp Bolingford, seventh man to bat, top-scored for ND with 18 before falling to George Gillies (1-13 from three overs), caught by Loffler.
Gillies and Stewart showcased the art of off-spin. Stewart had no luck: he had two catches dropped and beat the right-handed batsmen on the outside twice, the sign of a top fingerspin bowler. He got through his overs briskly, helping to keep the Bay six minutes in front of the rate required.
Credit goes to ND development panel umpire Richard Wilson (Counties-Manukau), whose diligence and rapport with the players were excellent.
Gillies flighted the ball beautifully and the fielding effort was great overall, enthusiastic and energetic.
Trowell (33) and Loffler (31 not out) nudged the ball around with a touch of class in a partnership of 65, before ND offie Logan Murray (1-6 from nine balls) took a return catch off Trowell. The Bay concluded a fantastic nine wicket-win soon after.
In the afternoon, Northland captain Lucas James won the toss and chose to bat.
Openers Ben Litchfield and Kieran McClintock worked hard on a warm day, with Brady Wright (24) and Ryan Krige (35no) complementing their efforts.
McClintock, who made 3no against Lakelands and got a golden duck against Coastlands, carried his bat for 52 — the northerners' first half-century of the tournament.
The Minties moments of the innings were Litchfield (19) and Wright both being bowled by outrageous slower deliveries from Luke Fisher (1-30) and Loffler (1-34).
The ball from Loffler, which pitched short of a good length and was on its way down again by the time Wright hit across it, was the roughest delivery of that type seen locally since James Penman of the Campion College Colts bowled flailing leftie Jonathon Wright (no relation to the Northland second drop) of Gisborne Boys' High School on HBR 2 in 2003.
The Taniwha posted 141-2 and steeled themselves for what could have been an exciting run-chase from the Bay, on the evidence of that morning's match-effort.
Poverty Bay could not repeat the measured approach of Game 3 and lost four wickets for five runs.
Northland opening bowlers Ryan Krige (2-5) and deceptive left-armer Brock Cameron (2-4), along with surprise-package off-spinner Litchfield (2-13), all bowled out.
Alex Shanks was Poverty Bay's top-scorer, with 11no from No.7. First drop Luke Fisher (9) and big leftie Jarrod Ormiston (8) were the next best.
The Bay kept Northland in the field for 20 overs, and finished at 44 for the loss of seven wickets.
The draw for the first round of 50-over matches — being played today and scheduled to start at 10.30am — was: Waikato Valley v Bay of Plenty Coastlands on HBR 1, Counties-Manukau v Bay of Plenty Lakelands on HBR 2, Poverty Bay v Hamilton on HBR 4, Northern Districts Invitation v Northland on the representative wicket.
Poverty Bay 77-1 (Nathan Trowell 33, Cohen Loffler 31no; Logan Murray 1-6) beat Northern Districts Invitation 76 (Depp Bolingford 18, Bakhtullah Khawrin 12; Nathan Trowell 3-12, Cohen Loffler 2-18).
Waikato Valley 146-3 (Riley McCullum 76no, Cameron O'Leary 44; Ranithu Rodrigo 2-22) beat Bay of Plenty Lakelands 109 (Sean Gapes 24, Josh Parsons 23; Hunter Crowe 5-23, Ryan d'Abo 3-14, Reilly Benefield 2-8).
Northland 84-8 (Sanchit Chopra 28; Rikesh Patel 3-20, Finn Williams 2-17) beat Counties-Manukau 80 (Aryandeep Mann 21; Lucas James 2-13, Cullen Hilton-Jones 2-15, Ryan Krige 2-19).
Hamilton 109-8 (Eli Parker 39, Angus Henry 26; Spencer Wills 2-19, Darcy Collett 2-21) beat Bay of Plenty Coastlands 106-8 (Billy Syme 23, Luke Scrimgeour 22; Aman Awasthi 2-14, Lucky Reddy 2-18).
Northland 141-2 (Kieran McClintock 52no, Ryan Krige 35no, Brady Wright 24; Luke Fisher 1-30, Cohen Loffler 1-34) beat Poverty Bay 44-7 (Alex Shanks 11no; Brock Cameron 2-4, Ryan Krige 2-8, Ben Litchfield 2-13).
Waikato Valley 123-0 (Riley McCullum 82no, Cameron O'Leary 33no) beat ND Invitation 142-7 (Sebastian Heath 42, Depp Bolingford 22, Abraham Wolland 21; Benji Bell 2-8, Hunter Crowe 2-16, Riley McCullum 2-18).
Hamilton 141-4 (Eli Parker 34, Angus Henry 30no, Lucky Reddy 22no, Daniel Kibby 22; Rikesh Patel 2-24, James Kingham 2-25) beat Counties-Manukau 108-6 (Aryandeep Mann 36, Fraser Farrell 24; Lucky Reddy 2-15, Liam Hayman 2-18).
Bay of Plenty Coastlands 119-5 (Kade Smit 39, Billy Syme 31no, Luke Scrimgeour 23; Cohen Stewart 2-4, Tom Yetsenga 2-25) beat Bay of Plenty Lakelands 117-5 (Harry Jones 35no, Tom Yetsenga 26no, Daniel Coster 26; Gus Tustin 3-12).