It beat Northland 52-9 in its bottom-four semifinal, making amends for its 15-13 loss in its opener against Counties-Manukau.
The team dominated the set piece, ensuring Northland struggled to get clean ball, while also delivering a better performance at the breakdown.
It was able to use that to score several good tries in the backs, as they passed well and played with more confidence than in their first game.
''The boys were all on the same page today,'' coach Luke Herden said.
''The things we had to rectify from the previous game, which was all about cleaning out rucks and getting some quick ball, that happened today and we scored some good tries from it.
''So that was very pleasing. We're now in a good space and we look forward to Saturday's game.''
Otago led 21-9 at the break before running in 31 unanswered points in the second half.
Locks Josh Hill and Keegan O'Donnell stood out, especially in the first half.
In the backs, first five-eighth George Witana directed play well and winger Tom Yarall scored two good tries.
Other tries went to Slade McDowall, Sam Pene, George Witana, Sam Dickson and Tatai Proctor, who scored two.
Witana also kicked six conversions.
Herden said the team used the width of the field well and scored some good tries
''There was some good counterattack, just really using the width of the field and some good distribution.
''That was the key: the accurate passing and having the guts to throw those passes, whereas you can always just tuck it and carry and get into a battle in the middle of the field.
''We were good at using the width of the field and we finished off some good work.
''Tom Yarall scored a couple of tries. He had to do a little bit but he had a lot of help from the players inside him.''
Otago plays off for 13th on Saturday.
It began in the bottom-eight section of the draw, having lost to both Canterbury and Tasman in the South Island qualifying phase.