Jimmy Neesham's second one-day century has led the Wellington Firebirds into the Ford Trophy final.
They will face his former team, the Otago Volts, at University Oval in Dunedin on Saturday in the decider, after beating the Auckland Aces by three wickets in the elimination final on Wednesday.
Neesham finished not out on 120 off 107 balls at Eden Park Outer Oval, having arrived at the crease in the 18th over with the Firebirds 86-3 chasing 237 to win.
Ollie Newton celebrates his fifth wicket for the Wellington Firebirds.
They were never behind the eight-ball in their innings, but did lose wickets at regular intervals, which made for a closer contest than they would have liked.
Neesham finished the chase in style, hitting Danru Ferns for six over the leg side in the 49th over.
The Aces were in trouble immediately after their captain Craig Cachopa won the toss and chose to bat, losing Ben Horne for two in the second over and Sean Solia for one in the fourth, both caught off the bowling of Ollie Newton, by Michael Bracewell at cover and keeper Lauchie Johns respectively
Auckland Aces seamer Ben Lister celebrates the wicket of Wellington Firebirds batsman Jakob Bhula.
Cachopa himself then went in the sixth, LBW to Newton for 15, and the right-arm seamer grabbed a fourth when he got danger man Colin Munro to nick one behind, leaving Auckland 44-4 with two balls remaining in the 10th over.
Neesham joined the party, strangling Mark Chapman down the leg side for 14, but from 58-5, the Aces began to mount a fightback, through Rob O'Donnell and Graeme Beghin.
The pair shared in an 129-run stand for the sixth wicket before Beghin departed for 69, caught behind off legspinner Peter Younghusband, who also snared O'Donnell for 54 shortly thereafter, caught by Firebirds skipper Hamish Bennett at midwicket.
Andrew Voerman • Sports reporter
The Aces had reached 173-7 at that point, with 11 overs remaining, and while their tail added 63 further runs, they didn't last 50 overs.
Danru Ferns added 19 and Matt McEwan finished not out on 33 off 32 balls, while Newton bowled Ronnie Hira to claim the second five-wicket bag of his one-day career, finishing with figures of 5-47.
Left-arm seamer Ben Lister had the Firebirds rocking early, inducing an edge from prolific opener Andrew Fletcher in the first over of the chase to give keeper Horne a simple catch, then adding Jakob Bhula the same way four overs later.
Ollie Newton took 5-47 as the Wellington Firebirds dismissed the Auckland Aces for 236.
Devon Conway and Michael Bracewell righted the ship, until the latter was out for 42, caught and bowled by left-arm spinner Ronnie Hira, who was the pick of the Aces bowlers and finished with
Bracewell became Lister's third caught-behind victim, for 41, to leave the Firebirds 128-4 just past the midpoint of the innings.
By then, Neesham was beginning to take control of the chase, and he made his way past 50 as he was joined by Malcolm Nofal, who took 28 balls to scratch his way to eight before giving Munro a return catch.
Graeme Beghin top scored for the Auckland Aces with 69.
McEwan removed new man Younghusband for a duck, setting up a tense finish,as the Firebirds still needed 57 runs off 67 balls with just four wickets in hand.
Neesham brought up his century in the 45th over, sweeping Hira to the deep square leg boundary, but lost Johns three balls later, run out for six.
From there, Neesham took full control, and though he offered up half a chance with 12 still required, the Firebirds reached their target with 11 balls to spare.
The Firebirds finished second after the Ford Trophy round robin, but gave up hosting rights for the elimination final with the Basin Reserve unavailable and Westpac Stadium deemed too unfamiliar, a move that did no harm as it turned out.
At Eden Park Outer Oval, Auckland: Auckland Aces 236 all out (Graeme Beghin 69, Rob O'Donnell 54; Ollie Newton 5-47) lost to the Wellington Firebirds 237-7 in 48.1 overs (Jimmy Neesham 120no; Ben Lister 3-51) by three wickets.
Ford Trophy final: Otago Volts v Wellington Firebirds; University Oval, Dunedin; Saturday, 11am