TOKYO – Tonga’s coach joked Friday that England star number eight Billy Vunipola, who has Tongan parents, should switch back to his home nation when the teams meet at the Rugby World Cup on Sunday.Asked for his reaction to Vunipola’s comments this week that he was still a Tongan, despite playing for England, Toutai Kefu quipped: “Well he should be playing for us then.”A young Vunipola was in the crowd when his father Fe’ao Vunipola played for Tonga against England in London at the 1999 World Cup, a game that finished 101-10 to the home side.Australian Kefu knows his opposite number Eddie Jones well but said he did not remind him of the last time they faced each other as coaches — when Kefu’s Tonga beat Japan.“I saw him earlier in the week, but I didn’t bring it up. I didn’t want to get him angry. We had a good laugh and I tried to get his team out of him,” he told reporters.And he was not shy of starting the mind games, saying all the pressure was on England.“This is a massive challenge for us, but we have nothing to lose and I think England are under more pressure than us. He’s picked a very strong team, but is there a weak England team? I don’t think there is with this squad.”Jones has picked his strongest available side for the opening clash, with only two players missing from the XV that obliterated Ireland 57-15 last month.For his part, Kefu picked a team packed with England-based players for their Rugby World Cup Pool C opener in the northern Japanese city of Sapporo.Fly-half Kurt Morath, Tonga’s all-time leading scorer with 340 Test points who plays for second-tier English team the Doncaster Knights, will lead the challenge.Morath is one of seven players attached to English sides, also including captain Siale Piutau who is at Bristol.Morath, Piutau, Sanatane Takulua and Sione Kalamafoni are the only survivors of Tonga’s last Rugby World Cup match against New Zealand four years ago.The Polynesian kingdom are heavy underdogs against 2003 champions England as they attempt to reach the quarter-finals for the first time in eight World Cup campaigns.Tonga (15-1)David Halaifonua; Atieli Pakalani, Siale Piutau (capt), Cooper Vuna, Viliami Lolohea; Kurt Morath, Sonatane Takulua; Maama Vaipulu, Zane Kapeli, Sione Kalamafoni; Halaleva Fifita, Sam Lousi; Ben Tameifuna, Sosefo Sakalia, Siegfried ‘FisiihoiReplacements: Siua Maile, Latu Talakai, Ma’afu Fia, Dan Faleafa, Nasi Manu, Leon Fukofuka, James Faiva, Nafi Tu’itavake