Kenya's Eliud Kipchoge thrashed the competition at Sunday's London Marathon, finishing in a course-record time of 2:58:09.
That translates to a blistering pace of 6 minutes 48 seconds per mile.
"Amazing," said Baxter Burgundy, 39, of Hatfield, England, who watched the race near the 20-mile mark. "I couldn't run that pace for one mile, much less 26.2!"
While the world record was never in jeopardy, Sunday's race delivered plenty of drama en route to the course record. Kipchoge ran with most of the favorites in the 3:10 pace group until the 14-mile mark, when he stopped to duck into a porta potty. That stop cost him nearly a minute, and it wasn't clear that he'd be able to catch back up to the pace group.
But catch up he did, rejoining the group by mile 15.
Around mile 17 he ran away from the 3:10 pace group leader and never looked back. The pace group leader, a local man named Jeremy Guttridge, 32, claimed second place, finishing in 3:09:23.
In the women's race, Jemima Sumgong, also of Kenya, won her first London Marathon title in 3:43:12 seconds.
But it was Kipchoge's course record that was the talk of the town.
"A sub-3:00?" exclaimed Bronwen Cotterill, 27, a graduate student who had just finished her first London Marathon. "I'm gobsmacked. That's fast."
Speed, however, is relative. Even Race Director Hugh Brasher had to admit that his event's brand-new course record isn't quite so impressive when compared against the word record of 2:02:57, set by Dennis Kimetto at the 2014 Berlin Marathon.
"I guess it was a pretty soft record, now that I think about it," said Brasher of his event's previous best time, a 3:02:12 set by Wilson Kipsang in 2014. "Weird that none of the really fast guys come here to race."
Still, by all accounts, Kipchoge was pleased with his performance.
"I know he wanted to break 3 (hours) today," said British sports writer Alan Tallmadge. "And he did, albeit with precious little time to spare."
"He's got to be happy about that."