Chantilly senior Sean McGorty won the boys’ seeded race and West Springfield junior Caroline Alcorta took the girls’ Saturday at the Glory Days Grill Invitational in Manassas. Both runners set course records while leading their respective schools to victory in the regular season finale for both teams.

McGorty brushed the competition at the start, ripping through the mostly flat five-kilometer course at Bull Run Regional Park before finishing to roaring applause in 14 minutes 45 seconds. The All-Met became the first boy in the 20-year history of the meet to break 15 minutes. On a breezy, cool day, he blew away the previous best time of 15:03 set by Handley’s Bobby Lockhart in 2001.

Chantilly was bracing for a stiff test from Severna Park, the top-ranked public school in Maryland. It didn’t happen. The Chargers ran well behind McGorty and easily dispatched the Falcons, 31-91. Georgetown Day was third.

Things were a lot tighter in the girls’ race but West Springfield prevailed for the second week in a row. The Spartans were able to hold off Washington-Lee and Chantilly.

Alcorta was the difference maker. The All-Met, who stands barely 5 feet tall, showed little distress except for when she accidentally went a few strides in the wrong direction during the last mile. She still was able to run away from Georgetown Visitation sophomore Emily Kaplan and break the tape in a personal-best 17:42.

Kaplan was runner-up in a personal-best 18:04.

“Having a little more experience, I know what my limits are,” said Alcorta, who is in only her second season running cross-country. “I can force the issue more. I’m so much more confident.”

McGorty’s never-let-up toughness was in full effect and nobody was able to match him. So on days like Saturday when he’s running all alone — that has been the case in every race except for a victory at Great American last month — he stays engaged by treating blowouts like the postseason races he’ll have next month when he is guaranteed to be flanked by some of the most elite runners in the country.

During the last mile on Saturday, for example, he imagined the flat terrain was the long approach to the line at the state meet, so he carried his arms a little higher than usual and concentrated on his finishing kick.

“It was go time,” McGorty said. “I feel mentally strong. I don’t really doubt myself at all.”