Deena Kastor was an emphatic winner of the Flora London Marathon women's race with an unofficial time of two hours 19 minutes 36 seconds.
Kastor dominated the race as he shattered the American record of 2hrs 21mins 16 secs she set three years ago in London when she finished third behind Paula Radcliffe.
The American's confident front-running display saw her shake off her lone challenger Susan Chepkemei before the 17-mile mark.
Kastor, paced to 23 miles by male training partner Mike McKeeman and then Kenyan Henry Tarus, never looked back after the decisive break.
The Olympic bronze medallist became the eighth woman to better 2hr 20min for the distance as she lived up to her pre-race favourite tag, also setting a world leading time for 2006.
It slightly improved the 2:19:51 achieved by China's Chunxiu Zhou five weeks ago in Seoul, and moved her to third place on the world all-time list.
Russia's Lyudmila Petrova a seasoned marathon performer, overtook Chepkemei in the closing stages to snatch second place from the Kenyan.
Mara Yamauchi, 10th last year, finished an outstanding sixth in an unofficial time of 2:25:12, which moved her to second place on the UK all-time list behind Paula Radcliffe.
In the men's race, Felix Limo denied fellow Kenyan Martin Lel a second successive title in a thrilling sprint finish.
Limo, last autumn's Chicago champion, won in the unofficial time of two hours six minutes and 38 seconds when he outpaced his countryman in the final 100 metres.
South Africa's Hendrick Ramaala matched his third placing of 12 months ago, while pre-race favourite Haile Gebrselassie fell off the pace in the final two miles.
