Aguascalientes - Belgian cyclist Victor Campenaerts set a new one-hour world record for distance covered on a track on Tuesday with 55.089km, edging past the previous record set by British great Bradley Wiggins.
The European time-trial champion established the new record at the Aguascalientes velodrome in Mexico at an altitude of 1800m, beating the previous record of 54.526km set in June 2015.
"I broke the magic 55km," the exhausted 27-year-old gasped after bettering Wiggins' mark by 563 metres, albeit under arguably easier conditions.
"I was too optimistic at first, and after half an hour I needed to set a new slower pace.
"I worked long and hard for this and the team were right behind me and now I paid them back."
Wiggins set the mark of 54.526km in June 2015 and there have been several failed attempts to break it since.
Wiggins was the 2012 Tour de France champion, also won the Olympic time trial that year, went on to clinch the 2014 world championships time trial and also won four further Olympic gold medals on the track.
Campenaerts raced under slightly different conditions to those faced by the track-trained Wiggins, and not only in the altitude.
International Cycling Union rules state any attempt must use a regulation track bike and the athlete must be part of the biological passport doping control program.
Pundits suggest, however, that the altitude alone could have given the Belgian up to a 1500m advantage on Wiggins.
That said, no hour record has previously been set at the Aguascalientes velodrome, which is at 1800m altitude, where the thin air is less resistant aerodynamically.
Campenaerts has been sleeping in simulated conditions of 3000m altitude, which increases the red blood cell count, with which the body delivers the oxygen that fuels physical feats, in his two weeks in Mexico.
His bike was constructed to his requirements without gears or brakes for weight and with straight handlebars for aerodynamics.
His bike frame also ensured he could take an identical riding position to his usual road style.
Winner of the recent time-trial at the one-week Tirreno-Adriatico, he is the double European time-trial champion and was third at the 2018 world championships behind Rohan Dennis and Tom Dumoulin.
The track at Aguascalientes was built from Philadelphia fired oak and has steep 48-degree banks, while the roof is an inflated wind-proof tarpaulin, creating ideal conditions for the highest speeds.