Scrum-half Cobus Reinach and wing Makazole Mapimpi both scored hat-tricks as South Africa ran in 12 tries in a 76-0 demolition of Romania in rainy Bordeaux on Sunday.
Reinach, 33, scored three of South Africa's first five tries to complete his hat-trick in just 21 minutes - 10 minutes slower than the treble he scored against Canada in 2019.
Mapimpi also dotted down in the first half, completing his own treble with two in quick succession in the second period.
"We prepared for the rain, we knew it was coming, but the only thing we spoke about was the physicality. We needed to bring it," said Mapimpi after the game.
"I don't put myself in front (first), it's all about the team. It's not about me walking over to score the tries. A lot of guys did well - Andre (Esterhuizen), Willie (Le Roux) - and I appreciate their work."
South Africa's win followed their 18-3 win over Scotland in their tournament opener.
Romania lost their second game of the tournament, after last weekend's heavy defeat to Ireland, and failed to score in a World Cup game for the first time since 2007.
With first-choice hooker Malcolm Marx ruled out for the tournament with a knee injury, Springboks head coach Jacques Nienaber named Bongi Mbonambi as hooker.
Nienaber made 14 changes from the Scotland game with an eye on facing Ireland in a tie to decide the winner of Pool B in six days' time.
"I'm especially happy with a couple of things we tried," said Nienaber.
"The three different hookers that we used - I thought that paid off.
"Then Faf (de Klerk) got some exposure at 10, so I thought a lot of things that we wanted to get out of the game, we got."
Lock Andre Gorin was handed his World Cup debut for Romania, known as the Oaks, by boss Eugen Apjok, barely two months out from his 36th birthday.
A storm was forecast with the skies overcast, which led to the 10,000-capacity fan park being closed for the day, but the humid conditions failed to stop the Springboks from starting strongly.
They raced into a 26-0 after less than a quarter of an hour thanks to Reinach's two early tries, Mapimpi's opener and a Damian Willemse touchdown for the bonus point, the quickest a side has scored four tries in a game in World Cup history.
The biggest cheer of the game from the 38,000 crowd came as Romania won a penalty just outside South Africa's 22m but winger Tevita Manumua missed his shot at goal, the closest the Oaks came to getting on the scoreboard.
After 20 minutes, with rain falling heavily, the players stopped for a water break, due to the hot and humid weather, but the downpour was unable to stop Reinach claiming his third.
Willemse made sure of the conversion as Nienaber's side led 33-0 at half-time, with some fans in the lower sections of the stands escaping from the rain.
The deluge from the sky stopped after the break but the surface remained greasy before usual back-rower Deon Fourie, making his first Test appearance at hooker since 2022 by replacing Mbonambi, crossed from a rolling maul.
Willemse missed his second from seven conversions, during the game underlining why Nienaber is considering calling up consistent kicker Handre Pollard, a World Cup winner in Japan, to his squad.
One of Willemse' final acts was to slot the extras from Grant Williams' try before scrum-half Faf de Klerk was given a run-out at fly-half with inconsistent Manie Libbok the only other stand-off in Nienaber's set-up.
In the final quarter, De Klerk converted two of four tries as winger Williams crossed twice, Mapimpi added his second and third before full-back Willie Le Roux completed the rout, with the Boks falling short of their record World Cup victory of 87-0 claimed over Namibia in 2011.