Rutherford was unbeaten on 47 from 39 balls, with Neil Broom down the other end on 69.
The pair were part of the consummate chase. Michael Bracewell smacked 60 from 49 balls as well, to help the Volts overhaul Northern's modest total of 181 and reach 187 for two.
But the much-needed bonus-point win was set up by a fine bowling display backed up by some tidy fielding.
Sam Wells and Jacob Duffy picked up three wickets apiece. Wells was particularly impressive, getting the ball to nip around on a green surface.
The win has seen Otago (13 points) climb two spots to fourth place and significantly boost its semifinal prospects, which looked bleak earlier during the campaign.
A win against Wellington in Invercargill on Wednesday will guarantee the Volts a place in the playoffs.
With one round-robin match remaining, Otago nurses a four-point advantage over the fifth-placed Northern Districts (nine points) with Wellington in last place with eight points.
Canterbury (27 points) Central Districts (18 points) and Auckland (17 points) are all through to the playoffs.
‘‘It was a good all-round performance and that is what we've been asking of the guys for a while now,'' Otago coach Nathan King said.
‘‘We are placed well at the moment but it is about making sure you are playing well going into the finals. Sometimes that is more important than where you might finish on the table.''
Northern Districts got a couple of rough calls during its innings and the bad luck started almost straight away.
Opener Joe Carter was given out lbw in the second over. Duffy celebrated but the replay suggested the ball was on a trajectory which would have taken it past leg stump.
Dean Brownlie was another in the unlucky camp. He was run out on 44 thanks to a superb piece of fielding by Jimmy Neesham, who hit the stumps from 35m.
The replay more than hinted that the batsman had made his ground, however. Umpire Barry Frost did not have the benefit of a second look, of course.
While Northern had cause for a good grumble, the visitors generally struggled on a slow and low surface.
The 73-run partnership between Brownlie and Daniel Flynn (34) was hardly pulsating stuff for a small crowd of about 80.
Otago always stayed in control of the run rate and it was frustration which eventually lead to Flynn's departure. He got an inside edge trying to whack the ball through the covers.
Wells got the reward and he continued to bowl a tight line, getting through 10 consecutive overs and taking three for 25.
He bowled Black Caps test keeper BJ Watling with a cracking delivery which nipped back in and clipped off stump, and Anton Devcich ran out of patience and hit a drive straight to Rutherford.
‘‘He has been attacked at various stages in the last couple of games but today he bowled on a wicket which offered him a little assistance and he bowled very nicely.
‘‘He did get the ball to seam and it was pretty tough to face.''
Brett Hampton gave Northern's total a little more substance with an entertaining cameo of 35 from 33 deliveries before he was bowled trying to sweep a delivery from part-time left arm spinner Anaru Kitchen.
Duffy and Neil Wagner returned to the bowling crease to wrap up the innings, with the former finishing with three for 39.
Neesham made his first return to the bowling crease since the first test against Australia last year.
He bowled with good intent but without reward. He could so easily have picked up Devcich's wicket when an inside edge narrowly avoided a collision with the stumps.
The only down side for Otago was that left-armer Bradley Scott picked up a minor muscle tear and will be sidelined for a a week or two. However, experienced spinner Nathan McCullum may return for the Volts if he passes a fitness test this morning.
‘‘We are really hopeful he will be available for us,'' King said.
Auckland booked its spot in the playoffs after beating Wellington by seven wickets at Basin Reserve while the match between Canterbury and Central Districts at Hagley Oval was abandoned due to rain after 18 overs.
