Brianna Rollins leaps to first place in 100-meter hurdles at U.S. trials

If anyone needed a reminder of how capricious hurdles races can be, two-time Olympic 100-meter hurdles medalist Dawn Harper Nelson was eliminated in the semifinals and American record holder Keni Harrison finished sixth in the final Friday at the U.S. Olympic track and field trials.

Brianna Rollins won an Olympic berth to Rio by winning the final in 12.34 seconds, the second-fastest time in the world in 2016. She will be joined by Kristi Castlin (12.50) and by Nia Ali (12.55), who won the NCAA title for USC in 2011.

Who missed the final was more surprising than the outcome. Harper Nelson was in shock after sloppy technique left her third in her heat with a time of 13.01, missing a chance to advance on time because Sharika Nelvis ran 13.00.

“You see it happen to others, but .01 is like, really? A dagger in the heart,” said Harper, who won gold at Beijing in 2008 and silver at London in 2012. “I was among some of the best in the world, and I’m supposed to step up and execute my race.”

Rollins was overcome with joy after she won. “I look forward to competing with these ladies, and hopefully all three of us end up on the medal stand,” she said.

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Defending Olympic 110-meter hurdles champion Aries Merritt, who underwent a kidney transplant in September, was third in his first-round heat and advanced to Saturday’s semifinals. Ronnie Ash had the top qualifying time, 13.39 seconds.

“It felt very easy. There was a lot of wind today so I was making a lot of mistakes,” said Merritt, who fretted that he hit several hurdles. “It just feels good to be back here competing.”

Big West champion Lloyd Sicard of UC Irvine ranked 17th with a time of 14.03 and didn’t advance. “I didn’t feel like I had the pop today but it’s OK. I’m happy that I came,” he said.

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Khallifah Rosser of Cal State L.A. was fifth in his 400-meter hurdles semifinal at 49.61 and didn’t advance. “I’m a little bit disappointed. I didn’t run as well as I wanted to but it’s all a good experience,” said Rosser, who plans to compete in an under-23 meet in El Salvador next week.

London Olympic silver medalist Michael Tinsley (49.15) and Johnny Dutch (49.20) had the top semifinal times.

Mason Finley won the discus throw final with a toss of 63.42 meters (208 feet, 7 inches). Tavis Bailey (61.57, 202) was second, with Andrew Evans (61.22, 200-10) third. All previously met the Olympic standard of 65 meters (213-3).

Jenn Suhr, the London Olympic women’s pole vault gold medalist, led qualifying by clearing 4.50 meters (14-9). The final will be Sunday.

helene.elliott@latimes.com

Twitter: @helenenothelen