The fall of the openers brought Cam Gordon and Sam Webb to the crease and both went about their work in the face of some accurate bowling.
Gordon was dismissed on 24, ending an innings-high 48-run partnership.
Alex Gordon was the next to go for 3 and when Webb was caught and bowled by George Ott (1 for 28), Northland were 112 for 5 with just over 14 overs to go.
The innings could have gone either way at that point and when Nathan Parkes (1) was sent back one run later, the wheels looked like falling off for Northland.
But Max Turner (24) and Cale Pooley (11) dug in for just under 10 overs to put on a valuable 29 runs.
Once Pooley went, Northland were promptly dismissed for 152.
Shaanveer Bhatia (2 for 20), Dinan and Sukhjit Singh (2 for 22) each took a brace while the fielding unit contributed two sharp run outs.
Hamilton started their chase in aggressive fashion, particularly through Oliver O'Meeghan (23).
Brayden Hutchinson-Walters made the first breakthrough for Northland, trapping Zac Ottaway in front for 3.
O'Meeghan and Jacob Parker saw Hamilton through to 48 before the introduction of Alex Gordon and Alexander-Crawford turned the match on its head.
Keeper Trigg snared his first sharp stumping to dismiss O'Meeghan off the bowling of the leg-spin of Alexander-Crawford (3 for 16).
Trigg added another stumping to his tally next over, this time from Alex Gordon's off-spin, which removed Parker for 9.
In his next over Alex Gordon trapped Luke White (2) in front to have Hamilton 50 for 4, but the spin twins weren't done yet.
Alex Gordon (3 for 18) showed off his variations to remove Jack Sturm for a seven-ball duck with the quicker one.
And when Alexander-Crawford had Singh lbw for just 1, Hamilton were left reeling at 65-6.
Dinan had quietly stuck around for 17 while he watched the carnage at the other end but his 52-ball vigil was ended by Alexander-Crawford with Hamilton still needing 76 to win.
The damage had been done. Hamilton had gone from needing 105 with nine wickets in hand to 75 with three wickets to go.
Turner (2 for 8) came on and grabbed an lbw to remove Shaanveer Bhatia for a 35-ball 6, then took the final wicket to end Hamilton's innings at 94 for the 58-run win.
Northland now head to Cobham Oval for the first day of the two-day final, starting at 10:30am today.