The composition of provincial rugby's top four was not clear until Auckland had beaten Tasman in the 70th of 71 regular season matches.
Top qualifiers Canterbury earned a home semifinal against Wellington despite being outplayed by Waikato in Hamilton.
In spite of the stirring victory against the more fancied Cantabrians, Waikato found themselves third on the table in the final shake-down, with Wellington grabbing the fourth spot.
Of the four remaining sides, Canterbury lack winning momentum, having gone down 26-6 to Waikato on Friday.
Both sides were under-powered through the absence of their All Blacks, but Waikato built their win on an outstanding display by their forwards, particularly in the scrums.
Waikato, who scored a try either side of halftime, kept Canterbury scoreless in the second spell - and tryless over 80 minutes.
In an intense first half, Waikato started strongly to lead 9-0 after 30 minutes with three Trent Renata penalties.
Canterbury always looked dangerous at the turnover, but Waikato secured too much possession, forcing the visitors into endless defence.
Eventually No 8 Alex Bradley bust the line. Renata's conversion gave Waikato a 16-0 lead, and only two late Colin Slade penalties before halftime gave Canterbury any hope.
Waikato extended their lead when Sosene Anesi touched down in the 55th minute after another powerful display of scrummaging.
Wellington secured their spot in the semifinals with a gritty 27-14 win over a feisty Southland in Invercargill last night.
Wellington's young but dangerous backline showed their lack of experience, while Southland, guided by the calming influence of first five-eighth Robbie Robinson, were slightly steadier and deservedly took an early lead.
But a composed kicking performance from youthful No 10 Lima Sopoaga, who landed two penalties and three conversions, and opportunist tries to centre Tajhon Mailata and wing Alapati Leiua helped Wellington subdue Southland, who led 14-10 at halftime.
Wellington's forwards raised their game after the break as their side quickly piled on 17 unanswered points to seal a fine win.
In other final round matches, Northland beat Bay of Plenty 36-24, Taranaki defeated North Harbour 49-47 in a 12-try thriller after Mike Harris' late conversion attempt for the losers drifted wide, Manawatu downed wooden spooners Otago 46-24 and last year's semifinalists Hawkes Bay beat Counties-Manukau 31-28.
Taranaki, Bay of Plenty and Southland complete the seven teams for next year's top tier, while Hawkes Bay, Northland, Counties-Manukau, North Harbour, Tasman, Manawatu and Otago will form the second-tier competition.