Fuller did not have the same success in the wicket column but he was just as instrumental.
He nicked out English import Phil Mustrad with the first ball of the innings and Duffy got rid of danger man Lou Vincent in his first over.
Colin de Grandhomme whacked 32 off 12 but was run out from a great throw from Neil Broom and a nice pick up from Nathan McCullum.
Craig Cachopa hit 43 from 33 deliveries and had his team on track. But when he got an edge of ten Doeschate's bowling, the match began to swing Otago's way.
Andre Adams and Kyle Mills were not able to get the 47 runs required from the last five overs with Fuller and Duffy returning to the bowling crease to restrict the former international's scoring opportunities.
Earlier, Otago made a terrible start with Hamish Rutherford (five) and Aaron Redmond (one) out before the fielding restrictions had been lifted and with just nine runs on the board.
Auckland's Michael Bates claimed both wickets with a fine opening spell, which included a rare wicket maiden.
Black Caps all-rounder Nathan McCullum came in at No 4 but could not get going. He was needlessly run out coming back for a second which was never on.
Having slumped to 53-5, ten Doeschate and Neesham combined in a valuable partnership.
Ten Doeschate had some luck with more than a couple of boundaries coming via the edge of his bat. But he has played four innings for Otago and he has made an impact in every match.
Neesham hit the ball superbly three sixes and six fours in a sparkling innings.
