RIO DE JANEIRO -- One day after parading around Maracana Stadium for a scintillating opening ceremony, Pac-12 Olympians joined the fray with more of the world’s elite athletes in the summer games’ first full slate of action on Saturday in Brazil. From hoops to swimming to soccer to volleyball and more, fans had plenty to watch throughout the day from the Conference of Champions.

SWIMMING

The women’s 400m individual medley race didn’t turn out to be much of a race in the end. USC’s Katinka Hosszu shattered the world record with a time of 4:26.36, nearly five seconds ahead of Stanford’s Maya DiRado (4:31.15), who gave the Pac-12 a 1-2 punch atop the podium. With the first-place finish, Hosszu earned the first gold medal for the Conference of Champions in Rio. She’s earned the nickname the “Iron Lady” for a reason: she’s also slated to swim 100m backstroke, 200m backstroke, 200m butterfly and 200 individual medley.

USC great Katinka Hosszu wins GOLD in 400m IM w/ world record 4:26.36!! #USC2RIO #FightOn pic.twitter.com/j29gFYEgor

— USC Swim&Dive (@USCswim) August 7, 2016

To cap off the night in the pool, an All-Pac-12 quartet took to the pool for Team USA in the 4 x 100m freestyle relay. Stanford’s Katie Ledecky and Simone Manuel teamed up with Cal’s Dana Vollmer and Abbey Weitzeil but the Americans (American Record of 3:31.89) settled for silver after a strong finish from Australia, which set a world record with a time of 3:30.65.

Vollmer, who gave birth to a baby merely 15 months ago, recorded the fourth fastest time in the 100m butterfly semifinals earlier in the evening with a 57.06 mark to earn a spot in Sunday’s final. The 28-year-old is vying to defend her gold medal in the event from the 2012 games in London.

Former Arizona swim star Kevin Cordes also advanced to his respective Sunday final, finishing the 100m breaststroke in 59.13 seconds to place fourth among semi-finalists for Team USA.

WOMEN’S SOCCER

The U.S. Women’s National Team withstood a strong test from medal contender France to claim a 1-0 victory in the group stage, following Wednesday’s 2-0 defeat of New Zealand. Once again team captain Carli Lloyd found the back of the net for the USWNT, but no Pac-12ers could score.

[Related content: Cal alum Alex Morgan highlights USWNT's win over New Zealand]

Then again, neither could France, despite applying a lot of late pressure to former Washington star goalkeeper Hope Solo, who recorded her second straight clean sheet. UCLA incoming freshman Mallory Pugh sat out the contest after suffering an ankle injury on Wednesday during an impressive Olympic debut.

Ali Riley (Stanford) and Betsy Hassett (Cal) started again for New Zealand’s White Ferns, who topped Colombia, 1-0, while UCLA’s Rosie White came on as a substitute to make her Olympic debut.

MEN’S BASKETBALL

The duo of DeMar DeRozan and Klay Thompson made their Olympic debuts for Team USA in Saturday’s 119-62 shellacking of China. DeRozan helped the Americans build a big first-half lead by scoring six consecutive points in the second quarter, finishing it off with a posterizing dunk.

USC alum @DeMar_DeRozan finished with 6 points, including two thunderous dunks, in his Olympic debut. #USC2RIO pic.twitter.com/4rhKWDV14G

— USC Men's Basketball (@USC_Hoops) August 6, 2016

Thompson earned a starting nod on the wing but finished just 1-for-6 from the floor for 2 points in 19 minutes of action. DeRozan totaled 6 points in his 18 minutes of play.

The Pac-12 also featured a couple of alumni suiting up for the Boomers, Australia’s national team which rolled to an 87-66 victory over France. The game was littered with NBA players, including Utah basketball alum Andrew Bogut who looked dominant en route to 18 points. Former Washington State center Aron Baynes also started, posting 14 points and 8 rebounds.

WOMEN'S BEACH VOLLEYBALL

America's vaunted beach volleyball team of Kerri-Walsh Jennings (Stanford) and April Ross (USC) made quick work of Australia's Nicole Laird and Mariafe Artacho del Solar, sweeping with a 21-14, 21-13 first-round victory. The "midnight match" on famed Copacabana Beach didn't start until early Saturday morning, but a big crowd was still on hand to see the American duo dominate offensively and defensively.

WOMEN’S VOLLEYBALL

Ex-Stanford star Foluke Akinradewo played a big role in Saturday’s 3-0 sweep by Team USA over Puerto Rico. With her team holding onto a one-set lead, Akinradewo helped deliver a crucial block to make the score 24-22 in a spirited second set that helped solidify a victory for the Americans. Former UCLA stalwart Karsta Lowe also contributed some big kills for the team.

MEN’S TENNIS

Steve Johnson, formerly of the USC men’s tennis team, claimed a 2-0 triumph over Barbados’ Darian King to advance to the second round of the men’s individual competition. Johnson will team up with Jack Sock on Sunday in a doubles match against Chile’s Julio Peralta and Hans Podlidnik-Castillo.

TABLE TENNIS

Two-time Olympian Lily Zhang (California) is the only Pac-12 rep in table tennis in Rio, and she did the Conference proud by claiming back-to-back 4-0 victories to advance to Monday’s third round of action.

.@usatabletennis' @lilyannzhang advances to the third round!!

Let's go #TeamUSA! pic.twitter.com/2UG1woJsiY

— U.S. Olympic Team (@TeamUSA) August 7, 2016

MEN’S WATER POLO

Team USA lost a 7-5 contest to Croatia to open up their summer games. Pac-12 Player of the Century and team captain Tony Azevedo (Stanford) scored a pair of goals to give the Americans a 4-3 lead but Croatia responded with four unanswered goals to put away the match.

FENCING

Stanford’s Vivian Kong made history by winning Hong Kong’s first Olympic fencing match on Saturday, before winning one more and reaching the round of 16, where she fell, 15-11, to Italy’s Rossella Fiamingo.

PAC-12 MEDAL COUNT 

Gold: 1 
Silver: 2 
Bronze: 0