Even in a highly controlled environment, the sub-two-hour marathon remains elusive — just barely.

Eliud Kipchoge of Kenya, 32, the reigning Olympic marathon champion, covered 26.2 miles in 2 hours 25 seconds early on Saturday in an extremely managed setting of pacing and drafting on a Formula One racecourse in Monza, Italy, outside Milan.

It was the fastest marathon ever run, more than two and a half minutes quicker than the official world record, 2:02:57, set by Dennis Kimetto of Kenya at the 2014 Berlin Marathon. But Kipchoge’s time will not be ratified for record purposes, mainly because of rules regarding pace-setting.

The attempt, called Breaking2, was as much a Nike marketing play and a laboratory experiment as a sports competition. Even so, Kipchoge shaved a remarkable amount of time off his best official finish: 2:03:05 at the 2016 London Marathon.

Saturday’s attempt was viewed by some critics as a publicity stunt rather than a valid sporting contest, emphasizing audacious performance over competition. It came weeks before Nike was set to roll out a new line of running shoes.