Eliud Kipchoge broke the course record at the Virgin London Marathon, retaining his title with the second-fastest run in history over the distance.
The 31-year-old Kenyan left the field trailing as he powered home in an official time of two hours, three minutes and four seconds.
Kipchoge 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.