Eliud Kipchoge broke the course record at the Virgin London Marathon, retaining his title with the second-fastest run in history over the distance, while compatriot Jemima Sumgong recovered from a fall to win the women's race.
Kipchoge, 31, left the field trailing as he powered home in an official time of 2.03:04.
He celebrated by raising his finger as he made the final turn but appeared to realise just before the line that he could have broken Dennis Kimetto's world record.
Kipchoge brought his hand to his forehead as he saw his time, which was just seven seconds outside Kimetto's mark made in Berlin two years ago, but was soon smiling again as he celebrated a stunning run.
Fellow Kenyan Stanley Biwott was second with a personal best of 2.03:51, while Ethiopia's Kenenisa Bekele was third.
Clare man Sean Hehir [2:17:20] was the fastest Irishman, with Belfast's Thomas Frazer [2:19:17] and Stephen Scullion [2:20:39] the other leading finishers.
Sumgong of Kenya recovered from a bad fall to win in an unofficial time of two hours 22 minutes and 58 seconds ahead of defending women's champion Tigist Tufa.
She took a tumble at around 23 miles, apparently tangling feet with Aselefech Mergia in an incident that also saw one of the favourites Mary Keitany fall.
Sumgong, who has been a runner-up in the Boston, Chicago and New York marathons, cracked her head against the floor but ignored her clear discomfort to rejoin the leading pack and eventually pass them, with Tufa failing to haul her in on the final stretch.
You fall over, bang your head on the road, and go on to win the #LondonMarathon. Take a bow Jemima Sumgong... https://t.co/jnP1PSJBrj
— BBC Sport (@BBCSport) April 24, 2016
Briton David Weir was again denied a record seventh title, as Swiss Marcel Hug won a sprint finish in the men's wheelchair race.
Weir finished second in 2014 and 2015 and was edged into third this time, with Switzerland's Hug powering towards the finish line ahead of American Kurt Fearnley.
Weir first won the event in 2002, adding five more titles in the next 10 years to go level with Dame Tanni Grey-Thompson with six victories.
Weir was in phlegmatic mood afterwards, insisting he was not fixated on a completing his magnificent seven.
"I think it's the media that hype it up so much, I don't think too much about it," he told BBC Radio Five Live.
"I've been racing here since I was eight years old, doing the mini marathon, and this is my 16th year in a row I think.
"To get six victories and be in the top three a number of years is not bad going. I've got to applaud myself for that and not get beaten up about the seven.
"If it comes, it comes and if it doesn't, it doesn't. I'm happy with what I've done in my career, but I'm not saying I'm going to retire, I still feel I have more to give and I'll be back next year."
American Tatyana McFadden continued her domination of the women's wheelchair race, claiming her fourth successive victory.
