The Blues are still in business, poised for another sudden-death Super 15 match overseas after their elimination finals victory win against the Waratahs.

Good teams go in for the kill. Neither the Blues nor the Waratahs were capable of applying that chokehold for long enough last night as they spluttered through their knockout match.

Their attacks were stilted, disjointed and often aimless and with both teams bringing their rugged defences, breaks were scarce.

So it came down to discipline, luck and which side would seize the moment. Frustration and anxiety surged through both sides as Blues marksman Lachie Munro kept the scoreboard ticking along.

As the game entered the last quarter Munro's third penalty gave his side a 16-8 margin, a slender but precious lead outside the converted try difference.

This was furnace time, when the blowtorch got hotter, the nerves returned as the prize of playing next week ground down.

Stephen Brett atoned for his tackling misses with a crisp pass to Joe Rokocoko in space, who threw a poor pass inside and forward.

Aerial pingpong got a workout as both sides switched off until the Blues found gold through comeback lock Ali Williams. The ball was spun through broken play to midfield, Munro shifted it quickly and Jared Payne drew two defenders and slipped the pass to Williams who had switched his line.

The big lock who had a strong allround game chuntered 20m and slid across the line for the score which confirmed the outcome.

The Blues last game at Eden Park this season drew only a small crowd of 16,100 on a night when the weather threatened to blight the match.

The hosts were as lethargic as their supporters for a large chunk of the opening quarter. Errors littered the Blues' initial work, they missed tackles by the barrowload, lacked unity at the breakdown while their lineout also misfired.

The backline stuttered and looked as though they had just met in the carpark. That lack of early sting suggested a long night for the Blues.

The visitors attacked the Blues' inside channels repeatedly where they found some troubled defenders and then turned the ball wide for Tom Carter to push through for the opening try.

It was a transformation which suggested trouble.

The Waratahs had started poorly with Kurtley Beale kicking dead before new hooker John Ulugia's first lineout throw was crooked, his second picked off and the scrum was penalised for an early engagement.

Beale banged another punt out on the full before the Tahs first win for the night came from a penalty.

They had half a chance when Ryan Cross got through a gap then a 5m lineout drive looked promising until Sitaleki Timani coughed up the ball.

Once Carter scored the Blues kicked back into gear. They belted out of defence on the back of a neat McAlister chip kick, a Rokocoko regather and Payne speared down the touchline.

He was herded into touch but from the subsequent play, left wing Munro crossed for a try and copped a knee in his ribs from Phil Waugh.

Several penalties soon after from Munro and the Blues were never headed. They have played better but bottom line they won.

It was the Blues first playoff appearance in four years, first at home in eight seasons, first appearance in Pat Lam's Super 15 coaching career and first side into the semifinals.

Both sides had to dig into their player reserves as the competition began their finals cull in the 19th week of the series.

The Tahs had skipper Waugh back at the helm but it proved to be his last game of Super rugby.

Blues exits for Rokocko, Payne, McAlister, Brett and John Afoa are on hold for another week.

Tighthead prop Afoa gets to play his 101st match for the Blues, in either Brisbane or Cape Town depending on the result of tonight's playoff match in Nelson.

The sides met in round-robin play more than two months ago when the Blues banked a victory.

Blues 26
Tries: L Munro, A Williams
Cons: Munro (2)
Pens: Munro (3), L McAlister

Waratahs 13
Tries: T Carter, L Turner
Pen: K Beale