By Saurabh Sharma

LUCKNOW, India South Africa's Quinton de Kock smashed back-to-back World Cup centuries as his 109 and Aiden Markram's 56 helped their side post 311-7 against five-time champions Australia on Thursday.

Asked to bat first after Australia captain Pat Cummins won the toss, South Africa made a watchful start and rode their luck before De Kock picked up where he left off in the win over Sri Lanka with eight fours and five sixes in his 106-ball knock.

South Africa skipper Temba Bavuma (35) gained two reprieves as Australia failed to hold onto difficult chances before Glenn Maxwell (2-34) snared him, but the Proteas marched on as De Kock twice hit Josh Hazlewood into the stands in the 23rd over.

Spinner Adam Zampa then removed the dangerous Rassie van der Dussen (26) but De Kock continued to plunder runs and brought up his 19th ton by pulling Cummins for a huge six shortly after the pace bowler had dropped Markram when he was on one.

Maxwell bowled De Kock out with one that crept through after hitting the left-hander's bat as he attempted a reverse pull and Markram fell to Cummins after his half-century, but more sloppy catching by Australia helped South Africa make a decent total.

(Reporting by Saurabh Sharma in Lucknow; Writing by Shrivathsa Sridhar in Bengaluru; Editing by Ken Ferris)