There are many obstacles facing Paula Radcliffe, the pin-up marathon mum and national hero, as she eyes Olympic catharsis. They range from asthma, pollution and high-tech running masks to the trio of women who ran faster than her last year. Now she can add her Great Britain team-mate to the list.

Mara Yamauchi won the Osaka International Marathon ten days ago amid stunned silence. The Japanese crowd looked on in horror as she passed the pink-suited glamour girl, Kayoko Fukushi, who later fell face down on the Nagai Stadium track, while her success created the merest ripple of acknowledgement at home.

However, the Tokyo-based diplomat has become a serious threat since taking a sabbatical from the Foreign Office and is on the brink of becoming an athletics star in her marathon-mad adopted country. “When I went past Fukushi I said to myself, ‘You're not making any friends here,' but the difference between winning and coming second is enormous,” Yamauchi said. “People are warming to me, especially when they find out I speak Japanese.”

Her winning time of 2hr 25min 10sec was a personal best and would have made her the world champion on the same course last September; instead, she led briefly before fading to ninth, but those lessons have been heeded. “I was disappointed with myself at the Worlds because, in terms of marathon strategy, I went mad,” she said. “I got carried away with the emotion and was swept along. I felt I had a good chance to go well and even get a medal, so I was disappointed with myself. My focus now is to be strong in the last 10k.”

There are plenty of sagacious observers who believe that Yamauchi could be the darkest of horses in Beijing. Radcliffe will be installed as a pre-race favourite after recording 2:23:09 on her return to the marathon in New York last November, but fears abound over the environmental factors. Radcliffe has played down the pollution but has tested the lightweight running mask developed by scientists at Brunel University.

Yamauchi, meanwhile, has no such problems. “I've done the asthma test that UK Athletics are doing for all athletes and I don't have any respiratory problems, so that's good,” she said. “It will be unrealistic to run a PB in those conditions, but I think the top six is realistic and Olympic champions have often been very unexpected. They are difficult races to predict.”

With Shigetoshi, her husband and coach, she has been to Beijing for a dry run, to drive and walk the course. “It can be a nightmare logistically, so it's good to visit beforehand and we've found a good Japanese restaurant,” she said. Noodles and seaweed form a key part of her diet.

Leaving her diplomatic job in January 2006 has allowed her more time to work on her strength and to rest. Previously, her duties were high-pressured and varied, ranging from organising diplomatic visits for Tony Blair to sharing a hot-sand bath with Jack Straw. The career break lasts until after the Olympics, but Yamauchi said that she may ask for an extension and has not ruled out the Games in 2012. “I'm about the same age as Paula and she has stated very clearly that she wants to run at the London Olympics,” she said. “My training is really beginning to bear fruit and the win has given me a lot of confidence.”

Living in a hot and humid climate, surrounded by a phalanx of world-class marathon runners, means she is well aware of the task in hand. “I'm second on the all-time British list but can think of ten Japanese off the top of my head who have gone faster,” she said. “The Japanese prepare very well and the Chinese have a group of juniors who've all just run under 2hr 30min.” The most surprising package in China this year, however, may just be the former Mara Myers.

Marathon contenders

Mara Yamauchi

Age 34 Lives Tokyo PB 2:25:09

Next race Matsue Half-Marathon, March 16

Best results Osaka marathon, 2008 (first); Flora London Marathon, 2006, 2007 (sixth); World Championships, 2007 (ninth)

Paula Radcliffe

Age 34 Lives Monaco PB 2:15:25

Next race London Marathon, April 13

Best results World Championships, 2005 (first); Commonwealth Games 5,000metres, 2002 (first); World Cross-country Championships, 2001, 2002 (first); winner of seven out of eight marathons; marathon world record-holder