ARCADIA -- For those who anticipated that the graduations of K.C. Cord, Lauren Hansson and Hilary King would result in the end of Harvard-Westlake's relay dominance on the track this year, Shea Copeland and Imani Cook-Gist demonstrated otherwise Friday night at the 45th annual Arcadia Invitational.

With the freshmen running the first two legs of the 1,600-meter sprint medley relay, Harvard-Westlake was locked in a tight battle up front with Taft.

Then Stanford-bound seniors Amy Weissenbach and Cami Chapus took over on the final three laps, not only lowering the meet record by more than three seconds, but producing the nation's fastest outdoor time this year of 3:56.34.

The mark was well below the standard set March 31 by The Woodlands, Texas (3:59.24) and just off the Wolverines' program record of 3:55.12, which they clocked to win the New Balance national outdoor title in North Carolina in June.

"I can't even tell you how proud I am of them. These are freshmen. They're just incredible and we're so lucky to have them," said Chapus, who anchored the relay in 2:09.9.

Although Chapus and Weissenbach won the sprint medley and distance medley relays last year at Arcadia, they missed setting the record in the former with Hansson and King by one-hundredth.

But with opening 200-meter legs of 25.5 from Copeland and 25.6 by Cook-Gist, followed by Weissenbach covering the second lap in 55.1, it wasn't a matter of if the 2004 meet record of 3:59.74 set by West Catholic High of Philadelphia would be broken, but by how much once Chapus received the baton.

"This group has never run together before, so we didn't know what to expect," Weissenbach said. "We know (Imani and Shea) have so much potential, so this is really exciting. It bodes well for the rest of the season, and the good thing is we can still improve on our handoffs."

Cook-Gist, who returned from a spring break trip to Tahiti earlier Friday, and Copeland -- who will run today on the distance medley relay with Elle Wilson, Chapus and Weissenbach -- demonstrated poise in their debuts at one of the nation's most prestigious events, helping Harvard-Westlake dominate a field that included Golden Valley (sixth, 4:10.75) and Taft (eighth, 4:15.29).

"I was a little nervous because this is a really big meet, so I just wanted to go out and run well for my teammates," Copeland said. "I'm so proud of all these girls. They did amazing."

Added Cook-Gist: "It's an honor to be able to run with (Amy and Cami). This is just incredible."

Despite a 4:52 anchor leg from Sarah Baxter, Simi Valley was unable to repeat as 4 x 1,600 relay champion, with La Costa Canyon winning in 20:23.88.

Erika Barr, Karla Vernola and Sarah Riggs also ran on the runner-up relay for the Pioneers (20:28.71), with Saugus placing 12th (21:20.81) and Thousand Oaks -- which received a strong opening leg from Caitlin Turner -- taking 14th (21:24.90).

Baxter received the baton facing a nine-second deficit against La Costa Canyon, but was only able to cut the margin in half since Kelly Lawson clocked 4:57 on the anchor for the Mavericks.

In what could be a preview of today's boys' 4 x 100 relay showdown, Rio Mesa -- led by UCLA signee Blake Selig -- edged Notre Dame, featuring junior Khalfani Muhammad, in the 4 x 200 relay by a 1:26.79 to 1:27.71 margin. Rio Mesa's performance, which included Cameron Roach, Drew Weisenberger and Darion Zimmerman, ranks 10th in the country this year. Chaminade (1:29.37) finished sixth and Oaks Christian (1:31.84) placed seventh.

After winning the girls' 800-meter sprint medley last year in 1:46.77, Oaks Christian placed third in a program-record 1:46.04. Ayzha Aupiu, Asha Culhane, Schuyler Moore and Danni Alakija produced the fourth-fastest effort nationally this year, behind No. 1 Long Beach Poly (1:44.37) and No. 3 Great Oak (1:45.36).

Abby King and Sarah Johnson joined Culhane and Moore to place sixth in the girls' invitational 4 x 200 relay in a program-record 1:40.72 for the Lions. Simi Valley placed second in the girls' rated 4 x 200 (1:42.74).

Golden Valley's Juan David Garcia, Nolan Del Valle, Carlos Lopez and Kristian Martinez took fifth in the boys' invitational 4 x 1,600 relay (17:28.26), won by Loyola (17:12.23). Quartz Hill captured the seeded race in 18:00.52.

Harvard-Westlake's Garrett Robinson, David Olodort, Judd Liebman and David Manahan placed fifth in the boys' invitational 1,600 sprint medley relay in 3:32.40, a two-second improvement on their 2009 program record. Chaminade was seventh (1:36.22) in the 800 sprint medley.

Newbury Park's Sean Fought, Kendall Esparza, Austin Lasater and Kevin Standridge won the seeded boys' 4 x 800 relay in 7:50.23 -- which ranks sixth in the country -- with Knight placing fourth (8:02.39). Notre Dame won the seeded boys' 4 x 110 shuttle hurdle relay in 1:03.74.

Alemany's Alex Mikrakis captured the emerging elite boys' high jump by clearing 6 feet, 5 inches -- with Quartz Hill's Lohnnie Tape-Jackson and Notre Dame's Elias tying for second (6-3 1/4) -- and Canyon's Robert Wolfe was third in the emerging elite boys' pole vault (14-3 1/4). Westlake's Nicki Ghazarian won the rated girls' 3,200 in 10:55.83, followed by Thousand Oaks' Melanie Joerger (10:57.41).

Thousand Oaks' Angelynn Caldwell and Quartz Hill's Allison Jackson both cleared 5-1 to tie for second in the girls' emerging elite high jump, with Thousand Oaks' Karsen Sper and Moorpark's Lauren Peterson also clearing 5-1 to place eighth and ninth based on misses. Simi Valley's Madisen Richards tied for fifth (17-4) in the emerging elite girls' long jump.

La Reina placed 10th in the invitational 4 x 800 (9:36.47).