Kane Williamson made 97, Ross Taylor 96 and Corey Anderson scored 40 and took 3-37 as New Zealand defended its total of 315-8, dismissing Sri Lanka for just 195 in 40.3 overs in a match laced with umpiring controversy.
New Zealand's strong form bodes well for the upcoming World Cup, which it co-hosts with Australia. Its six innings in the series so far, including the rained-out second match in Auckland, have contained four centuries by four different batsmen and five half centuries by five different players.
New Zealand and Sri Lanka meet in the opening World Cup match in Christchurch on Feb. 14.