Magic tablet helps Japan
The Asian champions, who pulled off the greatest upset in World Cup history by beating two-time world champions South Africa at this tournament, make up for their lack of height with their hi-tech attitude to the World Cup, added the former England captain.
"Each week we're going up against teams that are much taller than us, bigger than us," said Borthwick.
"Each time we've had to overcome that and they've done really well.
"Their work rate is outstanding and they've been tremendously physical," added the 35-year-old of the Japanese team preparing to play the United States on Sunday.
"One thing is clear: people think our drive is a threat now. They're having to commit a lot of players to stop it."
He said the Japan squad had come to England determined to show the country both deserves respect from their rugby peers and to host the 2019 World Cup.
"What we set out to do is build a rugby team that Japan can be proud of," said Borthwick, who was considered unlucky not to be selected for the 2003 World Cup winning squad.
"Their history of the World Cup has not been good – it's been terrible [they had won only one match prior to the present edition back in 1991 against Zimbabwe].
"The players have taken it upon themselves to inspire the next generation of players."
On top of tougher physical work, the players prepare themselves, said Borthwick who has been in Japan for the past year.
"In my experience, compared to players elsewhere like England, the Japan players do a lot more video work. The players have their iPads and computers and they're looking at footage all the time. It's a great credit to the players."
Following their incredible 34-32 win over South Africa, the Japanese lost to Scotland but beat Samoa 5-26 at the weekend.
A win against the United States could still see them into the quarterfinals for the first time in their history if Pool B leaders South Africa and second-placed Scotland slip up in their final matches against the Americans and Samoa respectively.
"The US have some very strong players, very powerful players. We know we need to be at our best this weekend," said Borthwick.
Agence France-Presse
