Outgoing national rugby team coach Eddie Jones bid farewell to Japan on Monday with a warning that the Brave Blossoms must keep winning to make the 2019 Rugby World Cup a success.

Jones, who led Japan to a historic three victories at this year's recently concluded tournament in England, is set to leave the country on Tuesday having completed his contract after almost four years in charge.

Jones is heading to South Africa to take charge of the Stormers Super Rugby side after turning down the chance to stay in the job and lead Japan at the 2019 Rugby World Cup on home soil.

The Japan Rugby Football Union has yet to name Jones' successor, but the departing coach believes that the overall success of the tournament will hinge on the Brave Blossoms' fortunes.

"The key to the success of the World Cup in Japan is going to be the quality of the national team," Jones told an audience at the Foreign Correspondents' Club of Japan in Tokyo.

"I think for the World Cup to be successful it is all about the national team winning the hearts of the people. If they are doing well and winning then people will want to be involved in the World Cup."

Jones coached his native Australia to the World Cup final on home soil in 2003, and the 55-year-old warned that the JRFU must hire someone who can handle the responsibility of leading the host team.

"When you are a home team, the pressure on that coach is enormous," he said. "You need a guy that has experience and understands how to manage his team in that quite hostile environment, because it is when you're the home team.

"It's going to be the same for Japan in 2019. The expectations for the next team is that they are going to make the quarterfinals. That's going to be tough."

But Jones also believes that his successor will have good materials to work with, citing the team spirit that led his side to a historic 34-32 win over South Africa in Brighton on Sept. 19.

"For Japan to beat South Africa is more than just talent," he said. "That is the uniqueness of Japanese sport, that if you are able to win the minds of the players and get the players to work in the same direction, then the human will of that team is massive."

Jones also warned that Japanese rugby needs to undergo root-and-branch reform if it is to consistently compete on the world stage, and predicted a difficult start for Japan's new Super Rugby franchise, the Sunwolves, when they begin play next year.

"The national team must be No. 1 priority, Super Rugby must be No. 2 and No. 3 needs to be the Top League," said Jones. "Unfortunately the problem in Japanese rugby is that the Top League funds everything, so they're not going to be No. 3.

"I can see some massive conflicts coming forward in Japanese rugby. That's something that's got to be done by negotiation. It can be done."

Jones downplayed suggestions that he could return to lead Japan in the future, but described his time in charge as "the most fun I've had in the game."

"As the ex-coach of Japan now, it's nice to look back on the achievements of the team," he said. "At the World Cup there were only two teams who beat South Africa — New Zealand and Japan. When did you ever think Japan would be spoken in the same terms as New Zealand?"