It took Aiden Markram only a couple of deliveries to realise it was going to be his day on a belter of a track, the South African power-hitter said after smashing the fastest ever century in men's World Cup against Sri Lanka on Saturday.

Three of South Africa's top four batters smashed rapid hundreds as they racked up a tournament record total of 428-5 en route to a comprehensive victory over the 1996 champions.

Captain Temba Bavuma fell cheaply but Quinton de Kock (100) and Rassie van der Dussen (108) forged a 204-run stand to lay the platform for Markram's fireworks.

"It's a strange one. I certainly didn't wake up this morning thinking it would turn out that way," Markram, who smashed a 49-ball hundred, told reporters.

"I gave a couple of bowls up front to get a feel of the wicket and eventually realised, watching Quinny and Rassie bat, and having that initial feel that it was a really good wicket.

"The outfield was really fast. The value for short is always there and that's almost what I was thinking all the time."

It rained 31 sixes and 74 fours in the run-fest at the Arun Jaitley Stadium as Sri Lanka made a spirited reply before being all out for 326.

A total of 754 runs were scored in the match and Markram was adjudged player of the match.

"You do a lot of planning and stuff like that before the game. I think it's natural for most teams to speculate on conditions," he said.

"When you get out and the wicket starts playing really well, it's a big sigh of relief. And then ... instinct does take over, it's sort of see-ball-hit-ball mentality."

For the first time in a World Cup match, three batters made a hundred in the same innings and all three South Africans broke into animated celebration after reaching the milestone.

"It's quite strange because you get this thing that just takes over your body at certain moments," Markram said.

"We are known to start very slowly, be it a series or a world event. We put a lot of emphasis on today's game, to start well... It's all of those emotions sort of mixed up and then building up and that just comes out."