MONZA, Italy -- Olympic champion Eliud Kipchoge was 26 seconds short of running the first marathon in under two hours on Saturday.
Kipchoge ran the 26.2 miles (42.2 kilometres) around an oval track in an impressive 2 hours, 25 seconds, unofficially smashing Dennis Kimetto's world mark of 2:02:57 by 2 1/2 minutes and raising hopes that one of world sport's most famous barriers can be broken.
"We are human. We are going up the tree ... I have lifted a branch and I am going onto the next one," Kipchoge said. "This is not the end of the attempt of runners on two hours."
The time will not be an official world record, sanctioned by the IAAF, due to variables like pacers entering mid-race and drinks being given to runners via mopeds.
Considered the best marathon runner in the world, Kipchoge broke his personal best of 2:03:05 set at the London Marathon last year. Kimetto set the world mark in Berlin in 2014.
Organizers first listed Kipchoge's time as a second faster, then changed it to 25 seconds off the two-hour mark.
"I rank this as the highest-ever performance in my life," Kipchoge said. "The aim of 'Breaking2' was to pass the message that running less than two-hour marathon is possible. That message is really special to me."
It wasn't a road race, with runners completing 17.5 laps around the 1.5-mile Monza Formula One track. The attempt was held on the 63rd anniversary of Roger Bannister breaking the four-minute mile in 1954.
Nike planned the record attempt for three years, including making shoes it said made runners four per cent more efficient. The Monza track was selected after extensive research that included average temperature, air pressure, and wind levels.
Two-time Boston Marathon winner Lelisa Desisa, from Ethiopia, and half-marathon world-record holder Zersenay Tadese of Eritrea were also part of the attempt, which started at 5:45 a.m. local time. They tried to help pace Kipchoge.
Desisa was dropped after 50 minutes, with Tadese falling back shortly afterwards. The duo still completed the marathon with Tadese shaving nearly four minutes off his personal best in 2:06:51. Desisa finished in 2:14:10.
That left just Kipchoge chasing the landmark time.
He passed the halfway mark in 59:54, but his average pace of 4:36 per mile was not quite enough, despite a final sprint to the tape.
Kipchoge needed an average of less than 4:35 per mile -- an improvement of about seven seconds per mile on Kimetto's record, or around 2.5 per cent.
"I tried to maintain the pace," Kipchoge said. "As a human you are not a machine so you cannot go 2.50 exactly, and those micro-seconds really have an effect."
