Leon Miles seemed like the man to beat in the 400-meter hurdles at the USA Track and Field Junior Olympics.

He wound up beating himself.

Miles clipped a hurdle early in Saturday’s semifinal heat, fell behind and never recovered. He wound up finishing 16th overall with a time of 54.65 seconds, and was eliminated from the competition in the 17-18-year-olds’ division.

“I thought I was real focused,” Miles said. “After the first hurdle, I stumbled up a lot. I got to a complete stop when I hit the third hurdle. That put me behind everybody.”

Miles had run a time of 53.60 seconds in the preliminaries, which was the fastest of any competitor. Seven of the eight hurdlers who advanced to today’s final bested that mark in Saturday’s semifinals in Jacksonville, Florida.

The top two in each of three heats, plus the two next best times advanced to the final. Lanorris Graden of the Miami Gardens (Fla.) Xpress Track team was the last qualifier, with a time of 53.65 seconds. Adran Carr of the Heavenly Track Club in Arlington, Texas, posted the top semifinal time at 52.76 seconds.

Miles, who was running for the Mississippi Heat Track Club, finished sixth in the third heat.

“It’s really disappointing,” Miles said. “I feel like I failed to support Mississippi as a whole, and my coach.”

The race was the last of the summer for Miles, a senior at Vicksburg High School. It capped a stellar 2015 season in which he won the MHSAA Class 5A championship in both the 110- and 300-meter hurdles and reached the semifinals in the 110- and 400-meter hurdles at the Junior Olympics.

Miles has scholarship offers from Southern Miss and Jackson State, and said he’ll now turn his attention back toward the 2016 high school season and defending his state championships.

“I had a good week as far as times went. I PR’d in both races. Next year I’ll look for new things and win a state championship in both races,” Miles said. “This is something that’s going to make me work harder toward school track.”