McKeon led out the national team’s stunning triumph in the pool on the opening day of the Olympic Games. In her first Olympics, the 22-year-old got Australia off to a solid start when she swum the first 100m in 53.31 seconds to stay in touching distance of leading United States.

Brittany Elmsie’s second leg kept the Australian team on track before the Campbell sisters, Bronte and Cate, swum right over the top of their biggest rivals in the pool.  Bronte’s stunning third leg had Australia in the lead and on-track to break the world record mark.

Cate then showed why she is one of nation’s best individual medal hopes at the Games with a dominant final leg which saw Australia clock a time of 3:30.65.

The United States came home for silver and Canada got bronze. 

The gold was Australia’s second at the Games and McKeon’s first at her maiden Olympics.

“It was so much fun,” McKeon said.

“I think being in the marshaling area with these girls makes you so more relaxed because at this big can meet you get so worked up. But that was so much fun being out there with these girls.” 

Earlier in the evening, brother Dave McKeon finished seventh in the final of the men’s 400m freestyle.

Fellow Australian Mack Horton won the event to give the nation our first gold in Rio.

In other sports, Shellharbour born Matildas Caitlin Foord and Michelle Heyman kept their medal dreams alive in a hard-fought 2-2 draw with Germany. Foord scored a crucial goal just before half time to have Australia on track for victory, but the German’s scored with two minutes remaining to nab a point.

Hockeyroos duo Grace Stewart and Casey Sablowski suffered a setback in a 2-1 loss to Great Britain in their opening match of the tournament.

Congratulations Emna, was awesome to watch and even better knowing your local connection! Anthony, Shellharbour City Centre

Congratulations, all of you so proud, go Australia Jayne Townsend, Mount Warrigal 2528

Well done Emma Wollongong is proud of you Joy garbutt, Fairy Meadow

Congrats Emma and the girls on an awesome swim. Very very proud of your achievement. John Ravnjak, Cordeaux Heights

Well done girls. Great win. Congratulations to all four of you o winning gold for Australia Morgan, Lake Illawarra

Congratulations Emma The Anastas Family, Kanahooka

So exciting, well done to the team Amanda, Corrimal

Congratulatioms Frances, Dapto

Fantastic congratulations Leanne Wright, Balgownie 2519

Congratulations! Julie Ramsay, Albion Park Rail

So proud of you and your team, congratulations on the win 🎉😃 Carolina Marin, Corrimal

Good onya Emma. You deserved this as did the team Lyndall, Lake Illawarra

I taught you at TIGS when you were á young girl. Fantastic to see you win today! Gina Cahill, Figtree 

Congratulations Emma McKeon on your gold medal win in 4 x 100 in women swimming. It was amazing and thrilling to see your whole team win with great difference and also create a New World Record of 3:30:65 time win. Congratulations again. VIJAY KUMARD, MACLEOD VICTORIA

Emma your a true, Champion Bessie Kallinikos, Farmborough Heights

Congratulations Emma....so proud of you. Xxx Anne Seibright, Oak Flats

Conratulation fantastic swim Donna, Coledale

Well done and congrats Dawn, Manyana

Congratulations Emma & team mates. All the very best for your races to come Trish Whant, Corrimal

Go Emma gold is priceless well done Vanessa, Mount Pritchard

Congratulations Emma! Al Trejo, Dapto

Congratulation on your win in the relay. Kay Boreham, Huskisson NSW

Congratulations!! Tim Buckley, Fairy Meadow

Awesome stuff Girls.."Aussie Aussie Aussie"😎👍 Danielle, Wollongong

Congratulations Emma so proud Denise, SHOALHAVEN HEADS

i am proud of the Australian swimming women’s team for winning gold good luck for more gold Emma. Aussie Aussie Aussie oi oi oi Ellee Habak, Wollongong

Great job Emma!! Congratulations!! Morrisey, Unanderra

What a fantastic swim Emma and team! Kim Holz, Albion Park

Dear Emma congratulations you've shined the whole of Wollongong with your proud gold medal. You've shined the Gong with your gold, congratulations and well done  Alibenjamin Bazzi, Wollongong

Good job girls Sharon, Merimbula

Well done , all the best Noelene, Gulgong

Congratulations on winning a gold medal Bella, Mangerton

You've made us all so proud Emma. Goosebumps and tears in the Brikich household. Well done on an awesome swim! Brikich Family, Coledale

CONGRATULATIONS on winning gold for Australia Krystal Cockerell, Lake Illawarra

Big congrats Ema☺🎇watchinh you in Croatia Jagoda, Wollongong

Hi Emma! You don't know me personally but you know my brother Ian Wilson. I watched you this morning and the race was amazing you all did a great job. We are all rallying for you girls and wishing you loads of Congratulations. Well done! Just enjoy every moment. Lesley Wilson, Goulburn

I used to swim in a lane alongside your squad at the Uni Pool. I take some of the credit for your swimming success ... because I swam so slowly, it must have inspired you to try and increase the number of times that you could lap me in 50m! :) So happy to see you win - actually a bit emotional, as I daily witnessed the effort you put into each training session. All the best with the rest of the Games! B. Horan, Figtree

Congratulations Shulei Chou, Wollongong

Congratulations Ros Hinkley 2527

You are totally awesome and It is amazing to see your hard work pay off in such a spectacular way! Keep aiming for the stars! Timothy John, Cordeaux Heights

Fantastic Emma you a true champion, proud day to be an Australian woman xx Eron coleiro, Airlie beach

Go the mermaid from the Gong Zoi Illawarra

Congratulations Emma and team mates. The Gong is very proud of all of you. Esin Ozturk Wollongong

go gong/ oi oi oi Fred, woonona

Congratulations Emma you really are a star love Sienna. Sienna Leslie. Fairymeadow

Amazing way to start your Olympic campaign dream. Big Julie pfeiffer, Albion Park Rail

Emma McKeon TIGS Class of 2012 winning an Olympic Gold Medal in Rio as part of the women's relay swim team. We are so proud of you Emma- congratulations from all at TIGS TIGS, WOLLONGONG

Awesome swim Emma Penny Moore, Bulli

Congratulations Emma, you make us proud(Wollongong) Mary Stone, West Wollongong

Good Job! Human, Greensborough 

Well done Emma Ben Neville, Eden

Just watched your race hold your head high beautiful girl you are the true meaning of a champion. You should be so proud Greig Turnbull, Fairy Meadow

congrats kiandra, vic

Don't let the 100Fly get you down Emma. You are brilliant swimmer. Keep going please. We after poring for you ALL THE WAY. Doll Ashenden, Mermaid Waters

Congratulations on winning a gold. You’re a superstar with many years to come. Ji latini, Wollongong

Well done Emma. Beverly, MT PLEASANT

Well done Emma on your gold in relay and making 100 fly finals, my son has trained with you at Ulladulla and today watched your race on ipad at school, keep up the great work. Julie, Batemans Bay

Congratulations Emma Khalilah Zipparo, Port Kembla

Well done Emma 👍 Ailani Zipparo, Port Kembla

We are so proud of you here from Wollongong Jo Martlew, Lake Heights

I would like to thank you for all your hard work you have done to get to Olympics to represent all of us in Australia. Kelly Patterson, Mango Hill Queensland

Congratulations Em on a fantastic swim by you and the team. We are all behind you here in Wollongong. Vesna Panovski, Gwynneville

Fantastic performance. Wel done. Marjan Kramer, Tongarra

Congrats Emma on getting Bronze, Silver and Gold. We love you! Kiara, Unanderra

Well done dear Emma Diosa & Waldo, Fairy Meadow

Congratulations Emma, so proud of you, sensational, love the Belsito family xxx Jenelle Belsito, Cordeaux heights

Congratulations Emma!! Amazing results for you & the team! xx Belinda Kinnear, Avondale

Congrats Emma, we think your awesome! Arthur family, Figtree

What great ambassadors Emma and David are for the Illawarra. Your dedication and commitment for all the hours up and down the black line is to be congratulated. Georgina and Charles, Shellharbour

A huge congrats! You have inspired my 6 year old who swims at McKeons swim school to be an Olympian one day! Melissa, East Corrimal

Amazing effort, Emma. What a fantastic achievement. Carmen, Farmborough Heights

Congratulations Emma Kevin Ramsay, Steamboat Springs Colorado (Wollongong expat)

All at JLDANCE wish you a big CONGRATULATIONS!!! So inspirational! Livin your dream!!! JLDANCE, Dapto

Congratulations. You are amazing!! Usain Bolt, Jamacia