The NSW Waratahs face an anxious wait to learn their finals fate after keeping their Super 14 title hopes alive with a dramatic 38-33 victory over the Lions in Johannesburg.

A 76th-minute five-pointer to replacement centre Tom Carter and contentious no-try ruling against the Lions in injury time allowed the Waratahs to escape Coca-Cola Park with the bonus-point triumph they so desperately needed.

The victory completed an unprecedented hat-trick of Super rugby wins by an Australasian team in South Africa and lifted the Tahs from seventh to third on the ladder.

But Australia's last remaining finals hopefuls were still underdogs to make the top four.

They were sweating on either the defending champion Crusaders slipping up against the injury-depleted Blues in Auckland or the understrength Queensland Reds upsetting the Hurricanes in Brisbane in the second match on Saturday night.

Even if they got a result, the Waratahs still needed the front-running Bulls to deny the Sharks a bonus-point home win in Durban in the very last game of the regular season early Sunday morning AEST.

"We can't control what happens in those games. We can only control what happened tonight and I'm really proud of the guys," NSW captain Phil Waugh said.

"To come away and win three games and get 13 points on the road is a really good effort, so very proud of the guys."

The one certainty is that the Waratahs' win ended the Brumbies' 2009 campaign.

After suffering a 10-7 loss to the Chiefs in Hamilton on Friday night, the Brumbies needed the Waratahs to stumble at altitude in Johannesburg to have any hope of sneaking into the semi-finals for the first time since winning the title in 2004.

And stumble they almost did, the Waratahs allowing the Lions to charge back from a 15-point halftime deficit to seize a 33-28 lead after 58 minutes.

Even after Carter restored NSW's advantage, the Waratahs needed a massive stroke of good fortune - some would say an act of extreme generosity from South African referee Marius Jonker - to hang on.

Lions centre Deon van Rensburg appeared to have dived over for the match-levelling - and potentially winning - try after the siren, only for Jonker to rule what looked a legitimate pass from five-eighth Andre Pretorius to van Rensburg forward.

The Waratahs had looked home and hosed after going to the break 28-13 ahead - and with the bonus point already in the bag - courtesy of tries to fullback Lachie Turner in the third minute, lock Dean Mumm in the 10th, Waugh on the half hour and winger Peter Playford in the 33rd minute - all converted by five-eighth Daniel Halangahu.

A try to halfback Jano Vermaak plus a conversion, penalty and drop goal to Pretorius were the Lions' only points of the first half.

But the home side piled on 20 unanswered points in 18 minutes - from converted tries to Vermaak and No.8 Willem Alberts and further penalty and drop goals to Pretorius - to set up the tense finale.

Boasting the best defensive record in the competition, the Waratahs may live to rue leaking so many points in their very last game.

Having finally broken the shackles to secure their first tryscoring bonus point since round three, the Tahs' uncharacteristic defensive lapse cost them the chance to improve their for-against differential.

It meant the Crusaders only needed to beat the Blues, without requiring a bonus point, to finish above the Waratahs on the ladder.

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