Desiree Linden floats home to become the first US woman to win the Boston Marathon since 1985 ©Getty Images

Desiree Linden surprisingly became the first American woman to win the Boston Marathon in 33 years today, and Japan’s Yuki Kawauchi of Japan also earned a shock win in the men’s race on a day of teeming rain and driving wind.

The coldest race day temperature in 30 years, hovering at 3C (38F) and a headwind of 10 miles an hour or more ensured unusual conditions for a race where there had been high hopes of a US victory in the women’s competition - but not on Linden’s behalf.

This was the first marathon win for the 34-year-old, although the 2012 and 2016 Olympian has many times demonstrated that she is a classy runner, having finished second in Boston seven years ago, just two seconds behind Caroline Kilel.

She also was second at the US Olympic Marathon trials in 2012 and after finishing seventh in the Rio 2016 marathon she was fourth in the Boston Marathon last year.

That said, most of the home attention was focused on higher profile runners such as 36-year-old Shalane Flanagan, who last November became the first US woman to win the New York Marathon.

Flanagan faded to sixth today, despite the fact that Linden hung back while she visited a portable toilet around 45 minutes into the race in order to help bring her Olympic team-mate from 2012 and 2016 back to the leading pack.

"Honestly, at mile 2, 3, 4, I didn't feel like I was even going to make it to the finish line," Linden said.

"I told her in the race, I said, 'You know, if there's anything I can do to help you out, let me know because I might just drop out.'

“When you work together, you never know what's going to happen.

“Helping her helped me and kind of got my legs back from there."

Japan's Yuki Kawauchi heads for his first major marathon victory in a rainswept Boston today ©Getty Images
Japan's Yuki Kawauchi heads for his first major marathon victory in a rainswept Boston today ©Getty Images

Linden took the lead around the two-hour, 12-minute mark, passing Gladys Chesir of Kenya and Mamitu Daska of Ethiopia.

Her finishing time was 2hours 39min 54sec.

Fellow American Sarah Sellers was second in 2:44.05, while Krista Duchene of Canada was third in 2:44.20.

On a day when the weather thinned the crowd and turned the race partly into an exercise in survival, Kenya’s 38-year-old defending champion Edna Kiplagat finished ninth in 2:47.14 – compared to her 2017 winning time of 2:21.52.

Before Linden, the last American woman to win the Boston Marathon was Lisa Larsen Weidenbach in 1985.

The last Japanese man to win Boston was Toshihiko Seko in 1987, but . Kawauchi finished strongly, overtaking Kenya’s defending champion Geoffrey Kirui in the final miles to earn victory in 2hr 15min 58sec.

Kirui finished second in 2:18.23, with US runner Shadrack Biwott was third in 2:18.35.

“For me, these are the best conditions possible,” Kawauchi told reporters after the race.

Seven of the top 10 finishers in the women’s race were home runners, with Rachel Hyland finishing fourth behind Linden and Sellers in 2:44.29, Nicole Demurcurio coming fifth in 2:45.52, Flanagan sixth in 2:46.31, Kimi Reed seventh in 2:46.47 and Joanna Thompson tenth n 2:48.31.

For the fourth year in a row, Marcel Hug of Switzerland won the men's wheelchair race, while American Tatyana McFadden won the women's wheelchair division for the fifth time.