SAPPORO – Eddie Jones believes his youthful England side are “tight” enough to cope with the ups and downs they will experience during a “rollercoaster” ride at the Rugby World Cup.Jones is a vastly experienced World Cup campaigner, who coached his native Australia when they lost in the 2003 final to England, acted as consultant to 2007 champions South Africa and masterminded Japan’s shock win over the Springboks in England four years ago.Now he finds himself in charge of an England team some are tipping to go all the way at Japan 2019 even though they crashed out in the first round on home soil at the last World Cup.The starting XV Jones has selected for England’s World Cup opener against Tonga in Sapporo on Sunday is the second youngest they have fielded at a World Cup with an average age of 26 years and 170 days.England captain Owen Farrell is still only 27 but flanker Tom Curry is 21.Jones, however, had no doubt his squad were ready for the physical and mental demands of the global showpiece.“What I’m delighted with is the way we’ve prepared for this World Cup,” he told reporters in Sapporo on Friday after announcing his team to play Tonga.“They’ve worked hard, physically I haven’t seen the side any better than they are at the moment and off the field they’ve worked really hard to be a tight team.“And that’s going to be tested in the World Cup because the World Cup is like a rollercoaster.”Explaining his analogy, Jones said: “We are at the top of the ride now, we are looking down — everyone’s nervous, everyone’s excited. You get down the first slope, you are not sure if you are going to throw up (vomit) or hang on.“You’ve got to adapt to that and the players have equipped themselves to ride the rollercoaster because there’s going to be some turns, there’s going to be some accidents, there’s going to be some fun.“We want to enjoy all of those things that come along and the team’s equipped to handle it.”England and Tonga will begin their World Cup campaign under the roof of the Sapporo Dome, a converted baseball stadium where a grass rugby pitch is wheeled in through an open wall.The dimensions will be slightly tighter than a traditional rugby ground but Jones said: “It’s a shorter pitch, we are just going to have to adapt to it and adjust to it as will Tonga. The boys are aware of it.“We are delighted to play at such an exciting stadium. You walk in there 45,000 people… there might be 45,000 people there tomorrow (when Australia play Fiji in the first of two World Cup fixtures in Sapporo this weekend) as well.“It’s going to be humming, it’s going to be fantastic. What a great way for us to start the tournament in such a fantastic stadium.”