Uganda's Joshua Cheptegei set a stunning new 5,000 meters world record at the season-opening Monaco Diamond League on Friday.

The world 10,000m champion clocked 12min 35.36sec at the Stade Louis II to shatter Ethiopian Kenenisa Bekele's previous best of 12:37.35, set 16 years ago in 2004.

"I've tried to improve on my speed," smiled Cheptegei when asked what he had been working on since his gold medal showing in Doha in September.

Cheptegei, who is the 2019 world champion over 10,000, took 22 seconds off his lifetime best at 5,000.

It was the standout performance of a stellar night in the Diamond League meeting that was the first full international gathering of the track and field season.

The Ugandan finished ahead of Kenyan duo Nicholas Kipkorir Kimeli and Jacob Krop at a Stade Louis II limited to 5,000 spectators because of the COVID-19 pandemic.