LONDON >> At the end, Ashton Eaton leaned forward, hands on his knees, out of breath. He looked like the world’s most exhausted athlete, not its best.

Eaton claimed the gold medal in the decathlon today. He fell short of the world record he set in June and short of the Olympic record, too. Still, at 24, years earlier than expected, Eaton staked his claim as the greatest all-around athlete in sports.

His winning score, 8,869 points, was the eighth-highest in Olympic history. Soon after the final event ended, Eaton grabbed the American flag, draped it around his back and made a lap around the stadium. His teammate Trey Hardee finished second, and it marked the first time the U.S. won two decathlon medals in the same Olympics since 1956.

The greatest all-around athlete is not the world’s strongest weightlifter, its fastest sprinter or its most nimble gymnast. He is an approximate of all three of them combined, dynamic and explosive, powerful and agile, action verbs in human form.

Mostly, he is versatile, and his many talents include sprinting, running, jumping, throwing and vaulting, all of which can be summarized in one word: decathlete. On Thursday, the world’s greatest all-around athlete added a qualifier to that title: Olympic champion decathlete.

The harbinger came in June, at the Olympic trials in Eugene, Ore. Eaton broke the 9,000-point barrier, the world record, established by Roman Sebrle of the Czech Republic, whose mark stood for 11 years.

But Eaton’s record came in Eugene, where Eaton competed for the University of Oregon and won three NCAA decathlon titles. His resume, stunning as it was, lacked a significant international title until Thursday.

In 10 events, spread over two days, Eaton made the decathlon look cool again. He called to mind the iconic decathletes who came before, men like Jim Thorpe, Rafer Johnson, Bill Toomey, Bruce Jenner and Dan O’Brien, none of whom scored as high as Eaton scored in June.

Jenner provided one indelible image from the 1976 Olympics in Montreal, before he graced a Wheaties cereal box and became the first athlete to marry a Kardashian. As he sprinted throughout the final event, the 1,500 meters, to break the decathlon world record, he looked exhausted and triumphant, a hero and his moment. John Belushi would later parody the run on “Saturday Night Live.”

Decathlon’s glory days eventually faded. Bryan Clay took gold in Beijing, and Nike later dropped him. Gone were the “Dan and Dave” advertising campaigns, even for gold medalists. The event’s long schedule was not suitable for television; the point system was difficult to explain and impossible for the average viewer to understand.

Eaton, famous in the track world, not so much outside it, said this week he could walk through Olympic Park relatively unnoticed. Imagine the same for Usain Bolt. Or Jenner, for that matter.

Eaton opened a sizable advantage Wednesday. He won the 100-meter dash, the long jump and the 400-meter sprint and set a career best in the shot put. His 100-meter time (10.21 seconds) marked the fastest-ever run in an Olympic decathlon. His long jump (27 feet) would have won a bronze medal in Beijing. He led Hardee by 220 points.

“Gotta go,” he told reporters afterward.

The first setback occurred Tuesday morning, after Eaton blazed through the 110-meter hurdles. His discus throw landed short, with a thud, and the gap over Hardee closed, albeit momentarily. Eaton extended his lead in the pole vault, posted a career best in the javelin and did well enough in the 1,500 meters to hold on.

For Eaton, it could be the first of many Olympic medals.