Lanning ton fires Australia to win over South Africa

The match brought together the only two undefeated teams at this year's tournament, with Australia already through to the semi-finals.

South Africa had more to play for as a win would have sealed a spot in the top four, and they set a solid target of 272 off the back of 90 from Laura Woolvardt.

However, Australia's formidable batting line-up easily overhauled the target with 28 balls to spare, leaving South Africa in a scrap for the three other semi-final berths with India, the West Indies and England.

"We had a great first innings and 270 was par, on another day the bowling attack would have defended it," said South Africa captain Sune Luus.

"We just lost it a bit on the field and probably lost a bit of focus... it won't happen again."  

Australia put South Africa in to bat after winning the toss but struggled to make early inroads as Woolvardt and Lizelle Lee put on an 88-run opening partnership.

Woolvart notched her fourth consecutive half-century at the tournament, supported by Luus's run-a-ball 52 and Marizanne Kapp's 30 off 21 balls.

Australia's openers departed cheaply but skipper Lanning stepped up to guide the six-time champions to 146-3 after 25 overs.

"It sort of became clear to me that I had to bat through after we lost a couple of early wickets," she said. 

It was Lanning's 15th ODI century and came of 92 balls, including 13 fours and one six.

Tahlia McGrath was Australia's next best batter on 32, with Lanning's teammates content to play cameo roles.

India, fourth in the table, play against Bangladesh later Tuesday in Hamilton.