Chris Lynn has been backed as Australia's long-term option to open in one-day cricket, but captain Aaron Finch conceded there was plenty of pressure on a misfiring batting unit to deliver with the World Cup looming ever closer.

Lynn was elevated to open alongside Finch in the third Gillette ODI Series match against South Africa in Hobart, pushing Travis Head down to No.4.

QUICK SINGLE Proteas sink Aussies to seal ODI series

The plan backfired when Lynn fell to the first legitimate delivery he faced, caught behind attempting to drive on the up against Dale Steyn, but Australia believe the attacking philosophy is sound with coach Justin Langer and Finch hatching the plan on match eve.

"We had a chat (Saturday) night and went through it and both slept on it and we were excited about it," Finch said.

"We thought it was a really attacking move to try and take South Africa head-on in that power play, something we hadn’t nailed in this three-game series so far, and we wanted to fight fire with fire.

"It didn’t pay off but that’s cricket. Some days it comes off and you get off to a flyer and that makes it, down the line, a lot simpler.

"It was an attacking option to put Chris at the top and change him and Travis. I think to put a couple of guys up there who can take it on and get off to a bit of a flyer is an attacking move."

Re-live Steyn's superb ODI campaign

One of the most powerful hitters in the game, Lynn has made his name, and fortune, in the game's shortest format and Finch said it could take Lynn some time to find his feet in the international 50-over game.

Sunday's match was just Lynn's fourth ODI, and with a high score of 44, he averages just 18.75 in the format with a strike-rate of just 84.26.

"He’s still relatively new to international cricket. He’s been around domestic cricket and various tournaments for a long time but international cricket he’s probably just still trying to find his feet a little bit," said Finch.

"He knows what works best for him in the shortest format and it’s probably just about finding that balance at international level as well."

Full highlights of Lynn's 135 against NSW

In domestic cricket, Lynn is a monster. A six-heating beast, he's dominated T20 tournaments around the world.

He transferred that skillset to the 50-over game in this year's JLT One Day Cup to lead all run scorers with three centuries as he piled up 452 runs in seven matches. He averaged 75.33 for the tournament, striking at 117.70 while batting No.3.

"I think the way he played in the JLT Cup this year was exceptional," said Finch.

"Being the guy who hadn’t played one-day cricket for a long time, that was really positive.

"The way he can turn a game ... we saw it briefly in Adelaide when he flicked the switch against (Proteas paceman Kagiso) Rabada.

"Yes, he got out but he changed the momentum of the game totally. That’s still definitely a thought going forward."

Proteas take out series after record stand

But while a dose of Lynn-sanity can break a game open, it comes at significant risk, something South Africa captain Faf du Plessis highlighted in Hobart.

Du Plessis said he felt Lynn would "give you a chance" while he admitted Australia's current middle-order malaise had captains sniffing blood in the field.

"You do feel (Lynn's) going to give you a chance from a bowling point of view," du Plessis said after wrapping up the ODI series 2-1.

"He's an x-factor and wants to go hard at the ball, so it creates an opportunity for us to try and get him out.

"He looks like he's comfortable when the ball is a little slower, in the 130s (kph), and he can bully that.

"But we do have pace in our attack to make sure he can't free his arms."

Du Plessis sneaks in review and saves Miller

That plan worked to a tee for the Proteas in Hobart, and it sparked another top order wobble. In the three-match series Travis Head managed just 15 runs, while Finch got 57 and Lynn 59.

Maxwell, who has been relegated to No.7 and an allrounder role, outscored them but only managed 61 for the series, including his 35 in Sunday's do-or-die knock in a difficult situation late.

"You do feel there is an opportunity for you if you get into the middle order," du Plessis said.

"If you get wickets up front, as an opposition captain you think there's a little sniff for you in the middle there."

QUICK SINGLE Finch explains Maxwell demotion

Finch said the returns from Australia's batters had been "disappointing" across the series, heaping pressure on a side that has now lost five successive bilateral ODI series for the first time ever.

"We're all under pressure when we lose, no doubt about that," said Finch.

"Between the batting line-up not having got it right for a little now while there's going to be some questions asked whether it's of 'Maxi', whether it's Lynn, Head, myself, or (Marcus Stoinis).

"There's going to be questions asked of all of us."

Australia's attention shifts to the T20 format for Saturday's match against South Africa on the Gold Coast before another three-game Gillette T20 Series against Virat Kohli's India.

Gillette T20s v South Africa and India

Gillette T20s v South Africa

November 17: Metricon Stadium, Gold Coast

Gillette T20s v India

November 21: The Gabba

November 23: MCG

November 25: SCG

Australia T20 squad: Aaron Finch (c), Alex Carey, Ashton Agar, Jason Behrendorff, Nathan Coulter-Nile, Chris Lynn, Glenn Maxwell, Ben McDermott, D'Arcy Short, Billy Stanlake, Marcus Stoinis, Andrew Tye, Adam Zampa.

South Africa T20 squad: Du Plessis (c), Gihahn Cloete, Junior Dala, Quinton de Kock (wkt), JP Duminy, Robbie Frylinck, Imran Tahir, Jonker, Klaasen (wkt), David Miller, Lungi Ngidi, Dane Paterson, Andile Phehlukwayo, Tabriz Shamsi, Rassie van der Dussen.

India T20 squad: Virat Kohli (c), Rohit Sharma (vc), Shikhar Dhawan, KL Rahul, Shreyas Iyer, Manish Pandey, Dinesh Karthik, Rishabh Pant (wk), Kuldeep Yadav, Yuzvendra Chahal, Washington Sundar, Krunal Pandya, Bhuvneshwar Kumar, Jasprit Bumrah, Umesh Yadav, Khaleel Ahmed.