An anxious Kate Murphy bolted from her mark on the anchor leg of Thursday’s Distance Medley Relay Championship of America at the Penn Relays, ready to chase down the two runners well on their way up the track.

If the Lake Braddock All-Met junior were to ever showcase her speed down the stretch — a trait that’s made her one of the nation’s most feared runners — this moment, with the Bruins eight seconds behind the leader, was the time.

But as Murphy settled into her lane around the turn, she suddenly remembered the plan.

“Sometimes I get too excited and press too hard at the start,” Murphy said, “so our coach [Mike Mangan] reminded us to stay patient and calm no matter what, and after the 800 mark, go for it.”

After two disciplined laps, Murphy broke through the frigid weather at Franklin Field, unleashing a blistering mile split of 4 minutes 37.65 seconds that put the Bruins in the lead for good as the bell sounded the final lap.

Heritage's Weini Kelati gets encouragement from fans as she wins the the 3,000-meter championship with ease at the Penn Relays in Philadelphia. (Doug Kapustin/For The Washington Post)

By race’s end, the Bruins had registered a winning time of 11:36.52, the fourth-fastest mark at the prestigious 122-year-old event and 10 seconds ahead of the runner-up Saratoga Springs (N.Y.). The accomplishment of winning the school’s first DMR at Penn Relays struck Murphy as soon as she crossed the finish line, when she pumped her fist and ran toward teammates Samantha Schwers, Shannon Browning and Skyla Davidson as they spilled onto the track.

“It’s pure joy,” Murphy said. “This is so special for us to add this to the legacy at Lake Braddock in an event where we can emphasize the importance of team.”

Murphy’s stride mirrored that of Heritage’s Weini Kelati just moments earlier in the 3,000 meters. As soon as the starting gun sounded, the All-Met broke away from the pack, quickly taking a lead that ballooned to 20 seconds en route to a winning time of 9:19.91, also the fourth-fastest time in Penn Relays history.

With each passing lap, the gasps and cheers drawn by the 19-year-old Eritrean’s dominant effort grew louder and longer.

Meanwhile, Kelati, who finished just off the national record of 9:08.6, found herself at ease while running an entire race by herself. Thanks to the sizable cushion, she, not her helpless competitors, could set her own pace, especially during the grueling final stretch in the chilly conditions.

“I know how to pace myself; I do it every day in practice,” said Kelati, who won the Foot Locker Cross Country Championships in December. “So it wasn’t really hard to be by myself. I’ve been waiting a long time for this and it feels great to win one of the biggest races.”

Scores of other local athletes made their mark Thursday on one of the sport’s grandest stages. A year after leading her team to victory in the DMR, Patriot’s Rachel McArthur earned a second-place finish in the girls’ mile.

In the field events, DuVal’s Madeleine Akobundu earned second in the long jump with a leap of 18 feet 3 inches, followed by Riverdale Baptist’s Taylor Woods, who recorded a jump of 18-2.25. In the pole vault, Battlefield’s Emily Harrison finished third with a mark of 11-5.75.

Several girls’ teams positioned themselves to join the annals of Penn Relays winners with strong performances in the slew of heats during the first day. Bullis ran Thursday’s fastest relay in the 4x400 meters, holding off a strong Nansemond River (Va.) team by less than a second to win in a time of 3:46.31. St. John’s also took first to earn a spot in the 4x400 final.

In the 4x800 relay heat, West Springfield qualified for the finals behind Reagan Bustamante’s split of 2:11.23, tops among Thursday’s competitors in the event. Also qualifying for the championship were C.H. Flowers in the 4x100 large school relay and McNamara, Bullis and Elizabeth Seton in the 4x100 small school relay.