Eliud Kipchoge of Kenya is the world's fastest marathon runner.
He confirmed that by storming to victory at the Tokyo 2020 Olympics, defending a men's title he had won at Rio 2016.
The double Olympic champion set the official world record of two hours, one minute and 39 seconds in September 2018.
The marathon may look like a slow long run, but looking at the splits it means super-fast 5km runs.
The fastest ever marathon win at the Olympics was 2:06.32.
That was by another Kenyan, Samuel Wanjiru when he clinched gold in Beijing in 2008.
Ever wondered how fast these marathoners run? Read on for more.
World record pace in context
To run a fast marathon, you need to have the ideal conditions, the right pacing, physical and mental strength, and endurance.
When the Rio 2016 and Tokyo 2020 gold medallist Kipchoge recorded a WR of 2:01:39 for the marathon in Berlin it went down to running each kilometre in 2 minutes 53 seconds.
The average finish for a recreational runner for the 5km is around 30 minutes. While chasing the record Kipchoge hit the 5km mark in 14 minutes 24 seconds.
He and the pacers crossed the 10km mark in 29 minutes and one second.
The average competitive time by advance runners is almost double Kipchoge’s competition running time, that is about 58 minutes.
Now imagine running the 5km in a blazing 14mins and 24 secs pace, eight and half times, to finish your race?
Breaking down the 2:06:32 Olympic men's marathon record
For a championship race like the Olympics, since there are no pacers, the race is often slightly slower.
Kipchoge's winning time in Sapporo was 2:08:38, a couple of minutes slower than the Olympic record of 2:06.32, that was set in equally hot and humid conditions.
The Olympic runners hit the 10km mark in around 30 minute.
To put this into perspective, the 30:00 is what an average city or park runner targets on a very good day for his 5km, yet elite marathoners take the same time to cover double the distance.
So, to do a marathon in the 2:06 pace a marathoner has to do his 5km runs in 14 minutes 50 second eight times in a row. Can you keep up?
How to watch the men's marathon at Tokyo 2020 in 2021
The men's Olympic marathon took place at Sapporo Odori Park, in the morning of Sunday, August 8, Japanese time.
You can watch replays of the event here on Olympics.com later on Sunday.
Find out where to watch all the action at the Tokyo Olympic Games live by clicking here.
For real-time updates on the sporting drama as it unfolds following our Tokyo 2020 live blog here.