After painstakingly inching its way towards Northern Districts' first-innings total of 275, Otago started to unravel when Neil Broom lost his long vigil on 54.
Northern Districts opening bowler Trent Boult picked up the next three wickets to complete a five-wicket bag on his debut for the association.
The rush of dismissals left Otago in the perilous position of 235 for nine and needing 41 from the last pair to get first-innings points.
Ian Butler and James McMillan added 21 in the most exciting period of the match, but rain then poor light brought a halt to play with Otago needing a further 20 runs.
Northern played its part in what was largely a sleepy affair by setting ring fields and persisting with the old ball for 23 overs past its expiry date.
When captain James Marshall eventually took the new ball it ushered in a dramatic change of fortune, with four wickets falling for eight runs.
"The softer ball was very hard to hit on there [pitch] and it was also reversing, and we felt that was our best opportunity of taking wickets," Marshall said, defending his decision to delay taking the new ball.
In hindsight, Northern might have already secured first-innings points had it taken the new ball earlier.
"I think at the the end of the season there are a lot of hindsights you can look at, but you have to make decisions out there and Boulty bowled beautifully with that new ball, and it did work," Marshall said.
"We're still in a position to take first-innings points and then we'll go from there."
With just a day remaining the match seems destined for a stalemate, which will make the battle for the first-innings points crucial.
Both sides will be determined to rescue something from what has been a frustrating game.
Having resumed yesterday on 116 for two, Otago looked to be reeling in the target at glacial speed, but reeling it in nonetheless.
Otago Craig Cumming added 16 to his overnight total of 69 before he was caught at the wicket attacking a Brent Arnel delivery.
Broom looked out of sorts for most of his marathon innings, but soldiered on to raise a half-century.
His 50 took 216 balls and a staggering 4hr 28min.
It was an exercise in patience but he ran out of it on 54 when he tried to wallop Arnel through the onside and was bowled.
His wicket triggered a collapse, with Otago losing three more wickets in quick succession.
Boult trapped Derek de Boorder in front then nicked both Neil Wagner and Mat Harvie out.
With Otago's first-innings hopes dwindling, Butler took the long handle to the attack and whacked a boundary through mid-wicket.
Marshall sent the field back but Butler got a top edge to a Bradley Scott bouncer and netted six more for the cause.
McMillan added insult to injury when he nicked a boundary through a vacant second slip, edging (pun intended) his side closer to its target.
Just after 4pm rain forced the players from the field and bad light prevented a restart.
Canterbury is in a battle to avoid an innings defeat in its match with Wellington at the Basin Reserve in the capital.
At stumps on the third day yesterday, Canterbury was 115 for the loss of three wickets.
It still needs 152 runs to make Wellington, which scored 428 for eight declared in its first innings, to bat again.
Resuming yesterday on 45 for two, Canterbury quickly folded under pressure from Wellington's international bowlers James Franklin (3-22) and Jeetan Patel (3-55).
Auckland, with just four wickets left, faces an uphill task as it chases another 183 runs for a win on the final day against Central Districts in Napier today.
Central was dismissed for 335 in its second innings yesterday, establishing a lead of 341.
At stumps, Auckland was in strife at 151 for six after losing its top order cheaply and seeing key batsman Scott Styris departing after a quick-fire 71 off 81 balls.
Earlier, Brad Patton anchored Central's second innings with a well-compiled 142, his maiden first-class century, after resuming on his overnight score of 61.
Scoreboard
Northern Districts
First innings 275
Otago
First innings (overnight 116-2)
C Cumming c McGlashan b Arnel 85
H Rutherford b Boult 0
G Todd b Boult 29
N Broom b Arnel 54
S Haig c Boult b Martin 2
N McCullum lbw Aldridge 23
D de Boorder lbw Boult 16
I Butler not out 19
N Wagner c McGlashan b Boult 2
M Harvie c Watling b Boult 0
J McMillan not out 7
Extras (5b, 12lb, 2nb) 19
Total (for 9 wkts in 116 overs) 256
Fall: 1, 70, 142, 145, 191, 227, 229, 235
Bowling: T Boult 17-2-53-5, B Arnel 29-11-51-2 (1nb), B Scott
23-10-48-0, G Aldridge 15-5-35-1, B Martin 27-10-41-1 (1nb), K
Williamson 5-0-11-0.
