Scrum-half Simione Kuruvoli kicked the Fijians to glory with 14 points coming from his boot at the Stade Geoffroy Guichard.

He helped his side go into the half-time break with a 12-8 lead before Josua Tuisova touched down after the restart.

Fiji's first-ever World Cup win, and third overall, against the Wallabies sees them overtake Eddie Jones' side into second place of the group behind Wales.

The triumph makes up for Fiji's heart-breaking defeat to the group leaders last week that saw a famous victory slip through their fingers late on due to a Semi Radradra knock-on.

"I'm emotionally drained at the moment," said Fiji head coach Simon Raiwalui after full-time against Australia.

"It was a great contest.

"It kept us guessing until the end.

"We pushed the boys to the limits and they've never once complained.

"I think there will be a few boys sore but I'm super proud."

Fiji's last win against Australia came on June 26 1954 in the second match of their two-game tour of the country, with the game ending 18-16 in front of 33,099 at the Sydney Cricket Ground.

"For some reason we were just off today - if you look at the stats, we dominated," said Jones.

"We scored two tries to one, but we were a poor version of ourselves.

"So there's a bit of soul searching to do, but it makes the Wales game pretty important."

In Pool D, England got the better of a spirited Japanese side 34-12 that could have come closer to victory if not for handling errors in key areas.

The Brave Blossoms bungled a simple loose ball on their own five metre line to give possession away resulting in a simple try for Lewis Ludlam to score the first try.

Nevertheless, they remained in touching distance before England scored fortunately through Courtney Lawes. 

The second row picked up the ball uncontested after Joe Marler appeared to knock it on, but later review found it struck his face and no foul play had occurred.

French Sports Minister Amélie Oudéa-Castera attended the match at the Stade de Nice to reportedly monitor security and transport following issues at England's opener with Argentina.

The first match of the day saw South Africa annihilate Romania 76-0 at the Nouvea Stade de Bordeaux in Pool B.

Springbok scrum-half Cobus Reinach scored a hat-trick inside 25 minutes as his side cruised to a 12-try victory.

Reinach's treble is the second-quickest in World Cup history, which he also holds after achieving the feat after 20 minutes against Canada four years ago.