Once Armitt (35 from 21 balls) and Kashmir Harypursat had put on 53 for the first wicket, Northland strolled to victory with captain Ben Smith steering his team home with three overs to spare.
Unfortunately for Northland they were unable to repeat their earlier performance, going down to Waikato Valley Plains by 14 runs.
Despite some below-par fielding, Northland were happy to restrict Waikato to 107 for seven in their 20 overs.
Trimble backed up his early form as he went onto claim three for 22, with Stobart [2 for 17], Armitt [1 for 17] and Eden Crawford [1 for 18] all contributing with their four over spells.
Northland's batsmen paid the penalty for looking to hit straight balls to the leg side as the top order collapsed to leave the innings in disarray at 49 for 7.
Hopes of a comeback were raised by a partnership between Watson [18] and Crawford, who was batting intelligently before being undone from a direct hit for 10.
A last wicket partnership of 25 between Stobart and Trimble kept Northland in with a slim chance until the final wicket fell in the 19th over.
Day two sees Northland taking on Bay of Plenty Coastlands in a must-win 50 over match.
Results:
Poverty Bay 99 (Nick Stobart 4/13, David Armitt 2/15) lost to Bellahomes Northland 100 for 4 (David Armitt 35, Ben Smith 14 n.o., Jacob Cherrington 14, Kashmir Harypursat 12).
Waikato Valley Plains 107 for 7 (Max Trimble 3/22, Nick Stobart 2/17) beat Bellahomes Northland 93 (Kurtley Watson 18, Nick Stobart 16).