When Sabastian Sawe said last week that it was "only a matter of time" before he would break the late Kelvin Kiptum's world marathon record, few thought that time would come in London on Sunday.
But this was bigger than just setting a new world record. In one hour 59 minutes and 30 seconds, the 31-year-old Kenyan rewrote the boundaries of possibility.
While the great Eliud Kipchoge became the first man to run a marathon in under two hours in 2019, that was not record-eligible as it was held under controlled conditions.
Remarkably, Sawe was joined in the record books by Ethiopia's Yomif Kejelcha, who finished second with an astonishing time of 1:59:40 to become just the second man to finish a marathon in under two hours.
In the women's event, Ethiopia's Tigst Assefa improved her own world record by nine seconds to set a new time of 2:15.41.
In a sport of 'marginal gains', all eyes are on how the trio thrived on a record-breaking Sunday in the capital.
The answer, many feel, is in the shoe.