Sydney McLaughlin won the 400-meter hurdles, defeating the 2016 Olympic champion, Dalilah Muhammad of the U.S.

TOKYO — Sydney McLaughlin recently said that “iron sharpens iron” when it comes to her relationship with Dalilah Muhammad. They are the pre-eminent practitioners of their craft, the two fastest women ever to run the 400-meter hurdles.

Few events were more highly anticipated at the Tokyo Games than the renewal of their rivalry on Wednesday at Olympic Stadium.

It was safe to assume that something extraordinary would happen, and McLaughlin delivered, breaking her own world record to win her first Olympic gold.

McLaughlin, 21, finished in 51.46 seconds. Muhammad ran the fastest time of her life to take the silver medal in 51.58 seconds, and Femke Bol of the Netherlands was third.

There have been various high-profile chapters between McLaughlin and Muhammad. At the 2019 world championships, Muhammad dipped under her own world record by 0.04 of a second to edge McLaughlin for the win at 52.16 seconds.

But at the U.S. Olympic trials in June, McLaughlin — so often considered the prodigy — met the outsize expectations that had shadowed her since she was a teenager by breaking Muhammad’s world record with a time of 51.90 seconds. Muhammad, after dealing with injuries and illness during the pandemic, finished second at the trials.

Those two races, though, were preludes to what played out on Wednesday, the fastest women’s 400-meter hurdles race in history — one day after Karsten Warholm of Norway had won gold with a time of 45.94 seconds in the fastest men’s 400-meter hurdles race in history.

Muhammad, 31, who had come to Tokyo as the reigning Olympic champion, went out hard to take an early lead. But McLaughlin was gaining on her coming off the final turn and outsprinted her in the final meters.

McLaughlin was a teenager when she competed at the 2016 Olympics in Rio de Janeiro, where she fell short of advancing to the final. It was a learning experience, and she leaned on some of those lessons in Tokyo. The Olympics were not new to her. She seemed utterly unfazed by it all.

She had spent the early part of the year refining her technique by running the 100-meter hurdles at the behest of her coach, Bob Kersee. The idea, McLaughlin said, was to “feel the rhythm of running faster.”

On Wednesday, she was the fastest in the world.