MOSCOW — Francena McCorory started strong in Monday's 400-meter final at the world track and field championships, but faded after the 300-meter mark and finished sixth.

"I'd be lying if I told you I wasn't disappointed right now," McCorory said shortly after posting a 50.68-second time.

A small consolation — it was one spot ahead of her seventh-place at the 2012 London Olympics.

McCorory, the Bethel High School and Hampton University graduate now a regular on the international track circuit, and USA teammate Natasha Hastings, blazed out to big advantages in Monday's final.

Coming around the final turn of the race, and already past the 300-meter mark, both seemed ready to run off with medals.

"Can't really tell you what happened at that point," McCorory said. "I guess it was just fatigue. We tired as the others came on."

And it turned into a dazzler up front as Britain's Christine Ohuruogu and Botswana's Amantle Montsho got to the finish line in virtual unison. Both were credited with 49.41 performances and it took a close look at the photos to determine that the British runner had won by the slimmest of edges.

The bronze went to Russia's Antonina Krivoshapka (49.78) over Jamaica's Stephanie McPherson (49.99) with the Americans, Hastings (50.30) and McCorory, in their slipstream.

A three-time NCAA All-American at Hampton, the 24-year-old McCorory had run a career-best 49.86 just a day earlier in the semis.

She'd planned to run at least 49.86 or better in the final, with an invitation to the podium — but it just wasn't to be.

McCorory will run again in the 4x400 relay, in which she is an Olympic gold medalist.

"This will make us even hungrier to win the (4x400) relay Saturday," she said. "We certainly know we can run better than we ran today."