Bay of Plenty ran out of puff but held on to beat Southland 24-22 in a pivotal Air NZ Cup rugby match at Mt Maunganui tonight.

At stake was a probable home quarterfinal for the winners of a clash between two teams were locked in fourth place coming in. Bay of Plenty achieved it courtesy of a lively first-half performance that saw them lead 21-3 inside 25 minutes.

They then had to withstand a powerhouse finish from the Southlanders, who dominated territory for large chunks of the game but were often let down by poor handling or option-taking. Both teams scored three tries but a four-from-four goalkicking display by first five-eighth Mike Delany proved important.

The game started at lightning speed, with few the hosts benefiting from the lack of kicking in general play, suiting their more abrasive loose forwards and backs. At the hub of their attack was sharp running halfback Ruki Tipuna, the diminutive No 9 eclipsing his frustrated Southland and All Blacks opposite Jimmy Cowan.

However, Cowan scored just before the break to keep his side in contention and they dominated much of a second spell where more kicking prevailed and their forward pack had the set piece edge. Southland's Robbie Robinson, who turned 19 last month, made the transition from fullback to first five-eighth with aplomb for the last half hour, asking countless questions of the home defence.

However, he missed a dropped goal with 2min remaining in his team's final chance to hit the front. Southland must now beat Canterbury next week to have any chance of securing a home quarter while Bay of Plenty won't have it easy themselves away to Hawke's Bay.

Southland's stingy defence, which had been the second best in the competition, was opened with ease in the early stages. The hosts crossed inside the first three minutes, when a series of slick passes presented a try to second five-eighth Nigel Hunt.

Southland first five-eighth Blair Stewart responded with a penalty but Tipuna extended the hosts' lead with a brilliant jinking run from the base of a scrum 25m out. Tipuna was at it again soon afterwards, breaking from a lineout to set up a try in the right corner to winger Lance MacDonald.

Cowan kept Southland in the hunt when he stretched out after taking a quick tap. Bay of Plenty weathered some early pressure in the second half before being awarded their first penalty of the game, which Delany slotted to hand them a 24-10 lead with half an hour remaining.

Southland's pressure finally paid off with neat tries to winger Matt Saunders and centre Kendrick Lynn in the 61st and 71st minutes to climb within two points.

Result of an Air NZ Cup rugby match at Mt Maunganui tonight:

Bay of Plenty 24 (Nigel Hunt, Ruki Tipuna, Lance MacDonald tries; Mike Delany pen, 3 con) Southland 22 (Jimmy Cowan, Matt Saunders, Kendrick Lynn tries; Blair Stewart pen, con, Robbie Robinson con). Halftime: 21-10.