The most terrifying moment in Caroline Alcorta’s running career came on the final leg of Thursday’s Distance Medley Relay Championship of America at the Penn Relays. Her West Springfield team was the favorite entering the day, but now it was in seventh place and fading quickly behind a hungry pack that seemed determined to crush the Spartans under the weight of expectations. Even for Alcorta, the most confident of athletes and one of the most decorated runners in Northern Virginia history, there was a moment of near panic.

“It’s the most frightened I think I’ve ever been,” Alcorta said. “Beforehand too, because nothing is for sure. I had all these scenarios going in my head of something that could go wrong.”

But Alcorta soon started picking runners off one by one, using her signature durability to scoot into sixth place, then fifth, then fourth with two laps to go. By the time she began her final lap, Alcorta was all alone in first, turning in a remarkable anchor leg to help West Springfield bring home the Distance Medley crown on the first day of the 120th running of the Penn Relays.

Alcorta sacrificed her option to run individual races at the Penn Relays to focus on her medley team — Katie Kennedy, Michelle Lipka and Reagan Bustamante — and the quartet gave the school its second consecutive high-profile win in the event after posting a U.S.-best time at the New Balance Indoor Nationals in March. It won by nine seconds on Thursday, a stunning result considering the team struggled to distance itself until Alcorta’s brilliant leg of 4 minutes 46.46 seconds. She called it the most important race of her career.

“This is number one,” Alcorta said. “As far as significance goes, this is the biggest thing to me right now.”

Elizabeth Seton’s Javonne Antoine lived up to her own moment in the triple jump too, hitting 12.69 meters (41 feet 73 / 4 inches) on a gusty day at Franklin Field. She stopped to stare at the judge’s scoreboard after the effort, because it felt that good. A full season’s work had led to this moment, and she nearly screamed while clapping with joy after the green digits flashed across the board. It was her best mark of the season, and it helped her finish second behind highly touted Georgia recruit Keturah Orji of Mount Olive (N.J.).

“I came here to do something,” said Antoine, who will compete at N.C. State next year. “Last year I did triple jump [at the Penn Relays] and came in sixth, and seeing how I’ve grown from then to now is just really big.”

Scores of other area athletes performed without stage fright at Franklin Field, which was lined with college coaches and thousands of spectators from across the country. In the first championship of the day, Dunbar All-Met London Freeland cut through the wind and rallied on the last leg of the 400-meter hurdles title race, finishing sixth in 1:02:26.

Clarksburg’s Claudia Ababio finished second in the shot put with a throw of 13.79 meters (45 feet 3 inches).

And on a day when Jamaican schools were in a league of their own in the relay heats, plenty of area schools put themselves in position to contend this weekend. In the 4x100 meter small school relay qualifiers, Bullis (47.70) and Riverdale Baptist (48.25) took fourth and fifth place respectively, giving both schools a chance to contend in Friday’s finals. Woodbridge (48.39) and Osbourn Park (48.30) qualified for Friday’s 4x100 large school championship, while Lake Braddock will be the lone area representative in the 4x800 meter championship after posting a heat time of 9:16.54.

Part of the Bruins’ surge was thanks to senior Hannah Christen, who bookended the effort with a second-place finish in the 3,000 meter race in the early evening. The gap between the events — about six hours — allowed her enough time to recuperate, and gave her enough juice to make a move on the final lap that vaulted her from fourth to a second place time of 9:37.57. She did it with the type of gumption that was visible inAlcorta’s performance minutes later.

“I was on the back stretch, and I was like, ‘I’m in fourth right now. Like, I’d be happy with fourth,’ ” Christen said. “And then I got to 150, and I was like, ‘No. I have to do it.’ So I just went after it.”