Japanese teenage daredevil Maya Sato says she shed her long hair, her cellphone and - almost - a few tears as she took on and beat the boys in a tough version of motorcycle racing.

At age 19, Sato last month won her first "Auto Race" contest, where riders speed around an asphalt circuit, sparks flying off their steel-capped boots, at up to 150 kilometres per hour on bikes without brakes.

The newcomer's victory has made Sato - the first woman to join the sport in 44 years - the bright new hope for revitalising Japan's version of speedway racing, where audiences place bets and riders compete for prize money.

Racing is in Sato's blood - she first rode a moto-cross bike at age six.

When Auto Race, or Oto Resu, opened its doors to women a few years ago for the first time since the 1960s, she quit school and joined a riders' boot camp that is so selective it takes only about one in every 50 applicants.

The switch to the gruelling, military-style training centre took some getting used to, says Sato - mobile phones and TVs are banned, and the young racers must finish their meals within five minutes.

"I'd be lying if I said I never felt like crying," Sato told AFP, recounting how she used to love fashion and shopping with her friends. "But I hate to lose. I had my hair cropped short to build up my fighting spirit.

"I have long dreamt of becoming a professional motorcycle racer, and my resolve was too strong to make me think about quitting."

Her father Seiya Sato, 52, recalled: "My daughter started riding motorcycles on her own at the age of six, as her brother and I were motocross riders. We bought a helmet for her and let her do as she wants."

In a nod to the high school life she left behind, Maya Sato named her racing bike "Serena" after a character in the US hit TV drama "Gossip Girl".

"Serena is described as a mentally tough woman," Sato said. "I wanted to become a strong woman to make it in this male-dominated world."

Sato's resolve paid off - she won the second race she competed in, in a July race on a circuit in Saitama, just outside Tokyo.

"I was frustrated because I only came in second in my debut race," she said. "People around me said it was a pity. But I was relieved when my parents told me that I did a good job," she said.

Auto Race, run by municipal governments, was hugely popular in post-World War II Japan, when the gambling, along with that on horse, bicycle and motorboat racing, helped to pay for Japan's reconstruction.

But audience numbers have steadily fallen since their peak in 1991, around the time when Japan's "bubble economy" popped, ushering in decades of slower growth, and as fans diversified into other sports.

"Generally speaking Japan's public has been losing interest in gambling as lifestyles have changed and tastes have shifted on how to spend days off and enjoy leisure activities," said an Auto Race spokesman.

As Sato has drawn attention to the sport, "we expect her to make Auto Race better known and help boost sales," the spokesman said.

Another racer, Katsuyuki Mori - a former pop star who quit the hugely successful boy band SMAP in the late 1990s to prove his mettle on the track - also thinks Sato can breathe new life into the sport.

"I hope she will do all she can to drive fast, become a top-grade rider and attract more fans," he told AFP.

Sato says she is inspired by Japan's new favourite women athletes, the women's football team "Nadeshiko", who won the World Cup in Germany last month.