Former Japan stalwart Luke Thompson, a veteran of 71 test matches for his adopted country, believes the Brave Blossoms are capable of beating Argentina and reaching their second Rugby World Cup quarterfinals with "a bit of luck" on Sunday.

The 42-year-old former lock, who played at four World Cups, was in Monaco and Nice recently for a few days in his role as a tour guide for Japan fans.

"I have me some hope that with the bounce of the ball and a bit of luck, the Japan boys can cause an upset," he wrote via email, having returned to his deer farm in New Zealand.