If England beats South Africa in the Rugby World Cup final on Saturday it would be appropriate if it celebrates not with a few Heinekens, the tournament's official beer, but with some Suntory brews.

For the Japanese brewer's rugby team, Suntory Sungoliath, has been giving its former boss Eddie Jones a big helping hand at training.

England coach Jones' association with the club began in 1997, and in addition to calling on the services of his former interpreter from his 2009 to 2012 stint with the Top League team to help with media duties, he has also arranged for opposition for his team on the training paddock.

"They have been here I think three or four weeks now," fullback Elliot Daly said Tuesday.

"It has been because we have had a few niggles and it's been good to have a full 15 to train against. (Scrumhalf) Genki (Okoshi) has been our boy.

"He has been with us probably the most amount of time. You can just see how excited they are to come and train. It is slightly different as well training against people that you don't train against every day, it makes you concentrate a bit more in training, definitely."

No. 8 Billy Vunipola concurred, saying Doshisha University graduate Okoshi was "the man."

"It's nice to have different people and different energy levels," Vunipola said. "We have had a few bumps and knocks but to have people like Genki in, not just to help with training but with the emotions of the group has been great. I think we have named-dropped them enough but he's a good lad."

The extra level of concentration inspired by the Japanese players' energy will be much needed given what is at stake at International Stadium Yokohama.

Saturday's final — a matchup between the No. 1 and No. 2 sides in the world rankings — will be contested by the "two most powerful teams in the world," England defense coach John Mitchell said.

"They play in a particular way, but you must always be prepared for anything that comes at us. They have a very clever (No.) 9, who is sharp.

"Polly (flyhalf Handre Pollard) is in really, really good form. They have four second-rowers who love winning the gain line. They have their own armory. It's exciting. Last week (against New Zealand), we dealt with a lot of speed, a lot of footwork. This week they are certainly going to be a team that is more direct."

Mitchell said that while the Springboks are somewhat predictable, England is capable of playing various styles and that "is our strength."

"Both teams enjoy dominating the gain like and kicking and are effective in that area (but) . . . we feel we are very adaptable — we don't just play one way," he said.

Asked whether he thought South Africa would be more physically imposing than the All Blacks, who England beat 19-7 in the semifinal, Vunipola said "Is that a trick question?"

"The All Blacks have been the best in the world forever and that physicality has helped them get to that stage. We set out wanting to be the best in the world, and we have to back up what we did last week. It can't just be a fluke."

"I think the challenge has been laid out by South Africa — as you saw them taking Japan apart and Wales. The challenge is going to be up front so we are going to have to be there, both mentally and physically."

And England will be relying on Okoshi and the Suntory players to prepare them for that possibility, particularly at Wednesday's training session, traditionally the hardest the players have in the buildup to a test.

"Tomorrow is a massive session for us, we always put massive emphasis on that session to prepare us as well as possible for the weekend, and it's going to be the same again," Vunipola said.

"Hopefully Genki and his boys bring their A-game tomorrow."