There are two kinds of roars that echo off Franklin Field’s venerable brick walls during the Penn Relays, and resonate on for years afterward.

The more famous of them is the “Wooooo!” that rises in the final meters of a race, encouraging the chaser and warning the chased as they race toward the finish line.

The other is the thunderclap that erupts when a track star is introduced by the public-address announcer to the masses in the stands. From Marion Jones to Justin Gatlin, Usain Bolt to Shelly-Ann Fraser-Pryce, the names and the noises are as big as they come.

On Saturday, a new star joined that illustrious list. Eight months after Trenton’s Athing Mu won two gold medals at the Olympics, a sun-splashed Franklin Field crowd of 38,843 gave her a full-throated welcome to her Penn Relays debut.

They cheered Mu’s name loudest when the lineup was read, and they raised a classic crescendo as she ran to victory in the Olympic Development Elite women’s 600-meter race. Mu overtook early leader Ajeé Wilson coming out of the final curve and cruised to a winning time of 1 minute, 22.74 seconds.

» READ MORE: Trenton’s Athing Mu wins Olympic gold for the U.S. in the women’s 800-meter run

“This is probably the best atmosphere I’ve had this whole 2021-2022 season,” said Mu, who shot to stardom by winning the 800-meter title in Tokyo, then anchored a star-studded 4x400 U.S. relay squad to gold.

Mu never ran at Penn in high school at Trenton Central, because she only ran for an AAU team, the Trenton Track Club. When she went to Texas A&M for college, the pandemic canceled the Penn Relays in 2021, the only season she ran for the Aggies before turning pro.

But she revealed that she came to Penn as a fan for some years with her AAU coach, so she knew a bit about what she was in for.

“Being on the track and competing is way different than being in the stands,” Mu said. “I was super happy that I had all the supporters here. People were telling me they were going to be here, and I definitely heard them in the crowd.”

Jamaica’s Natoya Goule, a longtime Relays participant in high school and college, finished second in 1:24.09. She enjoyed being back in front of the throngs of Jamaican fans in the stands.

“When they called Athing’s name on the line, every Jamaican cheered for her — we share her, you know,” Goule said to a hearty laugh from Mu.

Penn alum Nia Akins finished third in 1:25.14 in her first Relays since graduating in 2020. Wilson ended up sixth in 1:25.87.

“I wasn’t going to miss the opportunity to be back and see the [Penn] team and everything,” Akins said. “It’s like a reunion for us, which is really nice. And for one weekend, everyone gets to see how special it is here.”

Earlier Saturday, the crowd welcomed back Olympic champion Sydney McLaughlin for her first run at Penn since her high school days. McLaughlin also won two gold medals in Tokyo, in the 400m hurdles and 4x400 relay. She was the U.S.’ leadoff runner in the relay, with the squad also including Allyson Felix and Dalilah Muhammad.

(Felix, the most-decorated U.S. Olympic track athlete ever, was to run at Penn in a 300m race but withdrew a few days before.)

McLaughlin’s last run at Franklin Field was in 2017 for Union Catholic of Scotch Plains, N.J., up the road from her hometown of New Brunswick. She anchored the 4x400 back then, and ran a 50.37-second split that’s still the fastest for a high school girl in Relays history.

On Saturday, McLaughlin set another Franklin Field record, this time in the 100m hurdles: 12.75 seconds.

“I remember watching amazing pros run here when I was in high school, and just looking at them warm up and aspiring to be there one day,” McLaughlin said. “So being able to now be in that position and come back and inspire the next generation — not that they’re too far off — it’s just really cool. It’s a dream come true.”

» READ MORE: Sydney McLaughlin won 400m hurdles gold in Tokyo in a world record time