Umpire 'didn't hear' review: Proteas

South Africa insist they did not take too long to review a crucial lbw decision in their Gillette ODI Series-clinching win over Australia, simply they weren't heard by the umpire.

Proteas skipper Faf du Plessis and David Miller hit centuries and shared a 252-run partnership to set up the 40-run win in Hobart on Sunday.

But it could have been different if not for a controversial DRS moment.

Miller was given out lbw to Glenn Maxwell for 41 in the 33rd over.

But the decision was overturned on review after a lengthy deliberation between Miller and du Plessis.

Replays indicate it took the pair about 18 seconds to ask umpire Aleem Dar for a review, longer than the allowed 15-second window.

"Dave asked me what I reckon. I said 'I think it's pretty close but let's have a look'," du Plessis said.

"(I) turned around to the umpire and said, 'We'll refer that'. I don't think he heard me.

"Dave said about five seconds later, 'We'll refer it'. He (the umpire) was like, 'No your time's up'. I just said to him, 'We said like eight seconds ago'."

DRS ball-tracking showed the ball narrowly travelling over the top of the stumps and Miller was called back to the crease.

He went on to hit 139, with du Plessis reaching 125 as South Africa posted 5-320.

"It was one of those where you hold your breath and hope for the best," Miller said.

"Faf did it (ask for a review) first. Obviously the umpire didn't see or hear."

Shaun Marsh, who also hit a century, conceded the pair's partnership broke Australia.

"It was a big moment in the game but it wasn't out," Marsh said of the review.

"I thought they batted extremely well."

Australia v South Africa ODI series

First ODI: South Africa won by six wickets

Second ODI: Australia won by seven runs

Third ODI: South Africa won by 40 runs