On the smaller Eden Park Outer Oval ground, the chase looked possible at 163-2, with ND opener Henry Cooper following up his debut ton with 83.
However, spinner Tarun Nethula ripped through the order, finishing with 5-84 as Auckland notched a 71-run win with 10 overs to spare.
Auckland now hold second spot, 19 points behind Canterbury, with two rounds to go.
With 20 points on offer per round, they will likely need two outright wins for a chance at the title.
Wellington's hopes are negligible after a frantic finish against Central Districts.
CD were set 200 to win from 39 overs, and looked likely for a significant period as George Worker blasted 85. Needing 42 runs from 46 balls with eight wickets in hand, CD were in prime position, but the asking rate proved tricky as they collapsed, losing seven wickets for 32 runs.
With an over to go, CD needed 12 runs and Wellington two wickets, and neither side could triumph as the game ended in a thrilling draw.