Otago can still make the Championship playoffs with a win over Manawatu on Friday night, if Southland and North Harbour suffer losses in their final games.
However, the wooden spoon is also a possibility for Otago, if it falls to the Turbos and Bay of Plenty beats Waikato on Thursday night.
In possibly Tony Brown's penultimate game in charge of Otago before his fulltime shift to the Highlanders, the blue and golds never really got out of second gear in blustery conditions.
Too many missed tackles and a lack of execution handcuffed Otago and let the home side find some rare confidence, something it thrived under.
Bay of Plenty looked anything but a side that had only won a single game all season and punished Otago with its dominant pack.
''It was a very average performance,'' Brown said.
''We didn't execute anything, and when we don't execute we are a very average side.
''They have got a very good forward pack and in the conditions it suited them with their forwards ... they got a roll on and we started missing tackles and weren't able to slow their momentum.''
Playing into a stiff westerly in the first half, Otago opened the scoring with a Hayden Parker penalty goal in the seventh minute that gave him 100 ITM Cup points this season.
The visiting side dominated the first quarter of the game but could not capitalise further on the scoreboard. Bay of Plenty then produced a scintillating period of play to rock Otago with 19 points in 12 minutes.
Siaosi Iongi, who consistently put Bay of Plenty on the front foot with his strong running, set up the opener after busting four tackles and dashing 35m.
Otago's cover defence dragged him down 5m short, but the home side recycled the ball and pivot Dan Hollinshead scored from the next phase.
It was not long before the Steamers were in again, this time through hooker Joe Royal, who crashed over from close range after a good lineout maul.
Byron McGuigan then charged down a Michael Collins clearance, before scooping it up and racing 35m for the Steamers' third try in the 32nd minute.
Otago scored a crucial try on halftime through prop Aki Seiuli after Teihorangi Walden and Fa'asiu Fuatai combined down the left flank on the counterattack.
The try pulled Otago to within 19-10 and looked to have set the side up for a strong second half with the wind to its advantage.
However, 15 minutes camped inside the Bay of Plenty 22m to start the second half netted just six points as the Steamers stiffened defensively.
Bay of Plenty No 8 Carl Axtens then found a gap and offloaded to Hollinshead for his second try and Otago failed to fire another shot in testing conditions.
''It was a howling gale and showers all day - it was pretty ... [bad] to play in,'' Brown said.
''But we need to be better than that. We had an opportunity at the start of the second half to put them away but we couldn't turn our pressure into points.
''The longer they held us out, the more belief they got. In the end it was a result they probably deserved.''
Otago was looking forward to playing Manawatu at Forsyth Barr Stadium on Friday night and hopefully putting in a performance to be proud of, Brown said.
Otago under-19 beat Taranaki under-19 27-12 to finish fifth in the inaugural Jock Hobbs memorial tournament in Taupo on Saturday.
Wellington won the competition, claiming the Graham Mourie Trophy after beating Canterbury 32-21 in the final.
By Robert van Royen.
ITM Cup
The scores
Bay of Plenty 33
Dan Hollinshead 2, Joe Royal, Byron McGuigan, Leroy van Dam tries; Hollinshead 4 con
Otago 16
Aki Seiuli try; Hayden Parker con, 3 pen
Halftime: Bay of Plenty 19-10.
