The Wallabies overcame the early loss of fullback Reece Hodge and some stubborn resistance from the truly Brave Blossoms to chalk up five successive Test wins for the first time since the 2015 Rugby World Cup.

While never really looking like losing, the Wallabies struggled the shake off international rugby's biggest improvers and had to hold on in the tense closing minutes as Japan narrowed the deficit to just four points with a valiant second-half rally.

After having a hand in three of Australia's five tries, veteran playmaker Quade Cooper made way late for Australian rugby's fellow prodigal son James O'Connor, who coolly guided the Wallabies home.

All Blacks great Andrew Mehrtens likened the Brave Blossoms, under the coaching of Jamie Joseph and his assistant Tony Brown, to New Zealand's Highlanders and they certainly put the Wallabies under pressure with an up-tempo style.

Australian forwards James Moore, Ben Gunter and lineout weapon Jack Cornelsen, on his starting debut for Japan, all impressed as the Brave Blossoms also disrupted the Wallabies at the breakdown.

After clinging to a four-point lead at halftime, two tries in eight minutes from Wallabies power forwards Taniela Tupou and Rob Leota shot Dave Rennie's team out to a 27-13 advantage.

But when Brave Blossoms centre Ryoto Nakamura swooped on Cooper's long ball for a runaway intercept try in the 56th minute and added the extras, then a penalty, suddenly the Wallabies were under the pump.

"It was a really competitive game. Japan are just a side that are improving out of sight," Wallabies captain Michael Hooper said.

"We expected Japan to play expansive rugby and they delivered on that. They tested us in a lot of areas and it was a very close game in the end."

It wasn't until replacement hooker Connal McInerney crashed over in the dying stages were they safe from a historic first-ever loss to Japan.

Australia had opened the scoring with a try to winger Tom Wright in the seventh minute following a nice step and offload from Cooper.

Cooper's long ball also set up the Wallabies' second try to Jordan Petaia, a 14th-minute replacement for Hodge, who was forced off with a worrying pec injury.

The injury could place Hodge in doubt for the Wallabies' remaining three Tests in Europe against Scotland, Eddie Jones' England and Wales.

Having not played in three weeks since recording back-to-back wins over both world champions South Africa and Argentina, Hooper said Saturday's torrid work-out was just the tonic ahead of Australia's looming battles in the UK.

"We haven't played in a while so it was a high-paced game, a lot of ball movement, a lot of tackles to be made and some long phases of play too.

"So it's really good preparation for us."

But Rennie acknowledged the Wallabies must improve after labelling the performance as "rusty".

"And fairly frustrating. We played a lot of good footy but we just didn't kick the ball enough," Rennie said.

"We got some good go-forward and almost got sucked into going more phases when they had no cover at the back field.

"So that was disappointing."

Australian Associated Press