Kenya's Kelvin Kiptum set a London Marathon course record on Sunday, finishing in two hours, one minute, 25 seconds, nearly three minutes ahead of second-placed Geoffrey Kamworor.
Kiptum, 23, broke the record set by his compatriot, Eliud Kipchoge, by just 16 seconds.
Kiptum, who ran the fastest-ever debut marathon in Valencia last year, made his break at mile 19, establishing a solid lead to deliver the second-fastest marathon of all time.
The 23-year-old collapsed on to the ground, exhausted, after crossing the finish line. He ran the second half of the race in just 59 minutes and 45 seconds.
Kenyan president William Ruto has hailed Kiptum's win as ''decisive.'' The president also congratulated Geoffrey Kamworor, also a Kenyan who finished second.
Earlier, Dutch middle-distance athlete Sifan Hassan scored a stunning upset to win her debut marathon, an event she saw as a test which could pave the way to her competing over the marathon distance at next year's Paris Olympics.
Hassan, who has won Olympic gold in the 1,500 metres and 5,000 metres, made a dramatic comeback after an early injury to prevail over Olympic champion Peres Jepchirchir and defending London champion Yelamzerf Yehualaw in what organisers said was the best ever elite women's field for the event.
The 30-year-old looked to be in pa in around the hip flexor just under an hour in, falling behind as she stopped and stretched, but she caught up with the leading pack with just over six kms to go.
Hassan finished in 2:18:34 with a desperate sprint, shaking off second-placed Alemu Megertu of Ethiopia and third-placed Kenyan Jepchirchir in the final 100 metres. Ethiopia's Yehualaw finished fourth.
Hassan has snatched victory from the jaws of defeat before: in the 1,500 metres at the Tokyo Olympics she took a hard tumble, picked herself up and charged ahead to win gold.
