Hamish Rutherford posted his highest limited-overs score to help Otago secure a home venue for its playoff match with Auckland.
The captain's sparkling innings of 126 from 90 deliveries saw the Volts amass a mammoth total of 362 for eight at Queen's Park in Invercargill.
Wellington could manage only a paltry 141 in reply, with spearheads Neil Wagner and Jacob Duffy combining to take seven wickets.
With Auckland suffering a 47-run loss to Central Districts at Eden Park Outer Oval, Otago was able to leapfrog it in the standings and will host the Aces in a semifinal in Invercargill on Saturday.
It is quite a turnaround for the Volts. The team was stuck on the bottom on the table less than a week ago.
Rutherford downplayed his effort but he was instrumental in the victory.‘‘Obviously, it is nice to contribute,'' Rutherford said.
‘‘I've had a few starts recently but to go on was pretty pleasing. But as I said, it is more important that we've put in a strong performance with the finals series coming up.''
Rutherford has shifted from his usual spot at the top of the order to No4 this season.
With Otago spoilt for choice when it comes to top-order batsmen, someone had to drop down and the left-hander elected to make the move.
‘‘For my own personal development, I thought it was a good opportunity to take that role. It is a challenge but it has been going all right.
‘‘I do believe that it will help my game and hold me in good stead in the future.''
It certainly went all right yesterday. Openers Anaru Kitchen and Michael Bracewell got Otago off to a cracking start with a rapid stand of 76.
Otago's leading batsman, Neil Broom, got a start but nicked out on 17.
Rutherford joined Bracewell at the crease and the pair built on the momentum.
Bracewell was in punishing form but on 91 flicked a delivery off his hip to a fielder and was denied a century.
Rutherford kept the pressure on the opposition with a wonderfully paced innings.
He hit seven sixes and 10 boundaries in what was his fourth one-day hundred and highest score in coloured clothing.
It was an important knock too.
Had Otago lost yesterday, Northern Districts would have snuck into the playoffs ahead of the Volts.
It beat competition frontrunner Canterbury by three wickets in Mount Maunganui.
Otago's massive 221-run win was just short of resetting the record books.
The Volts 222-run win against Northern Districts at Molyneux Park last season remains its largest margin.
Its total of 362 was a ground record, eclipsing the 332 for six it scored at the venue in 2013-14, and nine runs shy of its highest total of 371 for seven, scored during a losing effort against Canterbury in Timaru in 2009-10.
Otago has lost as many games as it has won during the campaign and, overall, has not played that well.
But the team has come into some very good form at a fortunate time. A point not lost on the skipper.
‘‘With three games left, hopefully, there is no reason why we can't win it.
‘‘It sort of does not matter how you start the competition if you can build nicely into the finals.''
Wellington's capitulation was partly down to the desperate situation it found itself in.
To make the playoffs, the Firebirds had to secure a bonus point against Otago and that meant throwing the bat at the ball.
That provided Otago with a good opportunity to take wickets.
Wagner took four for 43 from 8.3 overs and Duffy grabbed three for 40 from five overs.
Black Caps all-rounder Jimmy Neesham, who has not long returned to the bowling crease after a lengthy layoff, took one for 26 from five overs.
He bowled the experienced Luke Woodcock.
●Despite Canterbury's loss yesterday, it will host Central Districts in the other semifinal.
The winner will secure a spot in the final on January 30, while the loser will play the winner of the Otago-Auckland semifinal in an elimination game on January 27.
