Otago will need wins over Southland and North Harbour today but will also have to post an impressive game tally to make the cut.
The more than usual number of upsets has kept Otago in the picture as the Bay of Plenty team is the only one to have won all its games during the first five rounds.
In cold and very wet conditions yesterday, the Bay quintet outclassed Otago to ensure they will be competing on Saturday.
Brent McEwan, the Otago No 1, was up against New Zealand representative Brad Kendall and found himself two down after some wayward driving and putts which continued to lip the cup.
Kendall made a birdie 3 on the ninth to turn three up - a lead he held until the 16th tee where he was dormie three up.
McEwan won the 16th when Kendall drove into the trees with thick undergrowth and lost his ball.
The match looked all over when McEwan drove under some pine trees at the right of the 17th fairway.
But, for the second day running, he punched a 5-iron to within a metre of the cup for a birdie three to keep the game alive.
Both players made four on the final hole with McEwan suffering his first loss of the week, albeit one down.
Otago No 2 Andrew Hobbs was in his element on the outward nine in tough conditions to lead by two at the turn.
But when the weather improved so did the form of Landyn Edwards and he birdied the final five holes to snatch the win.
Tyrone Ratahi (No 3) played some of his best golf of the tournament but was still only square with James Hamilton after 16 holes.
Ratahi three-putted the 17th green to go one down which then cost him the match.
Chris Snow was square after five holes with the Bay No 4 Sam Davis but he lost the next three holes to trail by three and never recovered.
Otago No 5 Mitch Bosley turned two down to Craig Hamilton but retaliated with birdies at the 10th and 14th holes.
But it was to no avail as Hamilton birdied 12 and 16 and took the match on the 17th green.
• Defending champion Wellington is coming into its own, APNZ reports.
Two of its most experienced campaigners, No1 Ben Campbell and No2 Thomas Spearman Burn, stood up in the closing stages of their pivotal match against Canterbury. Campbell made a clutch birdie on the 17th to go one up over rival Keelan Kilpatrick. Then Spearman Burn made an even better birdie putt on the final hole from close to 10m to win his match one up against Owen Burgess.
Campbell held on to win by the same margin on the last and the pair secured a pivotal point for Wellington in division one as it won 3-2 against an impressive Canterbury team.
Auckland dismissed in-form Taranaki 4- but cannot afford another loss against Hawkes Bay and Wellington.