He cuts an impish figure on the pitch, a pint-sized player among the giants on his defensive line.

But Yuto Nagatomo's unprepossessing exterior hides is a player who is built like a tank and runs like a racehorse — and could be Japan's secret weapon at the World Cup.

In Italy's top-flight, Nagatomo has won a regular spot in the starting lineup at Inter Milan — unlike his more famous Japan teammate Keisuke Honda, who failed to make an impact after making a much trumpeted mid-season transfer to city rival AC Milan.

What makes Nagatomo special is his flair for attack.

Both at Inter and with Japan, Nagatomo's trademark is galloping down the right side on the counter-attack and sending in pinpoint crosses — or even scoring himself. He netted five times and bagged six assists for Inter this season. And he has found the net three times in international matches.

At the World Cup, Nagatomo is aware that his main job is at the back — especially since Japan has shown itself to be vulnerable in defense in recent matches.

"In the first match (against Ivory Coast), there are great players ... we need to stop them," Nagatomo told reporters after training on Monday. "Then, if I can score, that's great."

But one of the ways Nagatomo defends is to add zing to Japan's attack.

"He doesn't need to invent things like Honda," said Paolo Condo, lead international football writer for Italy's Gazzetta dello Sport. "Nagatomo just has to run, run, run. And Nagatomo is a player who runs."

It's a crowd-pleasing style that has combined with a sly sense of humor to help Nagatomo win the hearts of Italy's notoriously demanding fans.

In the Brazilian heat, Nagatomo's speed and stamina will be a particular asset for Japan, as he is known to wear opponents down with his relentless runs. He will be on the constant lookout to feed Honda, Manchester United's Shinji Kagawa and in-form striker Shinji Okazaki, who scored 15 times this season for his Bundesliga club Mainz.

But Condo also warns that playing for Inter is different from playing for Japan.

"At Inter he works well because there's the defense of five. So he always has a defender who covers for him when he goes forward," said Condo. "The national team plays with four defenders, so he possibly has to be more careful, faster in pulling back."