Japan coach Eddie Jones believes his side is capable of making the step from Rugby World Cup pretenders to genuine dark horses, but warns time is running out to improve before the tournament kicks off next month in England.

The Brave Blossoms lost 45-20 to a strong World XV side in Tokyo on Saturday to begin their final stretch of warmup games before their World Cup opener against South Africa in Brighton on Sept. 19.

Japan next takes on Uruguay in a pair of home friendlies before facing Georgia in a final warmup in Gloucester on Sept. 5, and Jones is hoping for a similar workout to the one Springbok legend Bakkies Botha and his World XV teammates gave his players on Saturday night.

Botha led a team featuring four members of New Zealand's 2011 World Cup-winning side and a host of young Australian fringe players hoping to force their way into the Wallabies squad for next month's tournament.

Jones entered the post-match press conference having heard that New Zealand had crushed Australia 41-13 while the game was taking place, and the coach took it as proof that anything can happen in rugby.

"We're not far away," said Jones. "It seems like we're a long way away, but we're not far away. You see what happens in test rugby. Two weeks ago, Australia beats New Zealand convincingly. Today, New Zealand puts 40 points on them.

"How do you work that out? How can you change that much in two weeks? You can change. Our job is to make sure the players keep believing that. If we do that, we'll go to the World Cup and we will change Japan's rugby history."

Japan scored the first try at Prince Chichibu Memorial Ground through Karne Hesketh and kept pace with the World XV until the visitors imposed their authority and put the game to bed in the second half.

Jones acknowledged that some of his players had been affected by the pressure of the occasion, but warned they will have to deal with it when they face the Springboks, Scotland, Samoa and the United States at the World Cup.

"We haven't got many players with World Cup experience," said Jones. "We only had seven players who have been to the World Cup. We lack big-game experience — I can't hide from that fact. You see that in games like today.

"The only way we are going to get better is to play games. Are the players worried about it? They probably are. But they've got to learn to cope. There's no other way of doing it."

Japan scored a second-half penalty try to add to Hesketh's effort, and 10 points from the combined boots of Ayumu Goromaru and Harumichi Tachikawa.

"If you make mistakes against an opponent that is stronger than you, they will score from them," said fullback Goromaru, who landed two of three penalty attempts. "If I can convert my kicks from 50 meters then the team can ride that wave. It's frustrating, but we have more games to come and I want to practice hard."

Several of the World XV were hoping to catch the eye of Australia coach Michael Cheika before he names his final squad for the World Cup, including 194-cm, 123-kg Fiji-born winger Taqele Naiyaravoro.

Naiyaravoro scored three tries in a dominating performance, staking his claim alongside fellow Wallaby hopefuls James O'Connor, Nick Cummins, Sean McMahon and Christian Lealiifano.

"My goal now is to try to make the World Cup squad," said the 23-year-old Naiyaravoro. "There were opportunities out there tonight, and we'll see what happens from here.

"Japan is up there. They have been coming up rapidly and they're not far off. They're already up there. So it should be interesting and I'm very happy to see that. Japan coming up is wonderful to see."

Botha, a World Cup winner in 2007, will not play at this year's tournament having retired from Springboks duty last November. But the second-row forward also believes Japan can compete on the world stage.

"I think the physical side of their game is there," said Botha. "We worked very hard for every point that we earned tonight. The physical aspect of the Japanese side is there, and I think Eddie has a foundation that he can work on and know what he can expect at the World Cup.

"He's the kind of coach that will definitely build from there, to know where are the weak points that he needs to work on and where are the strong points that he just needs to fine-tune. I still enjoy the physical side of it at the age of 36. I love it."