Needing 65 to win from 20 overs, Meg Lanning scored an unbeaten 36 from 21 balls and Alyssa Healy 23 from 24 balls to propel Australia to 68-1 in just 8.1 overs.
The pair shared in a second-wicket partnership of 63 after Australia had lost the wicket of Beth Mooney for two in the second over.
Shanika Bruce was the lone wicket-taker for Barbados. She took 1-7 from the two overs she bowled.
Australia won the toss and sent Barbados to bat on a grassy pitch that held no terrors. Openers Deandra Dottin and Captain Hayley Matthews got the Caribbean representatives off to a good start getting to 20 inside four overs.
However, it all began to go wrong with the fifth ball of the fourth over bowled by Darcie Brown. Matthews had punished the bowler with two boundaries before getting out to an injudicious shot for 18.
She was the only batter to get into double figures as Deandra Dottin went for eight as Barbados slipped to 37 for 2. Shortly thereafter Kycia Knight was out for nine pulling Tahlia McGrath down to backward square where Megan Schutt held onto an easy catch and leave Barbados in serious trouble on 39-3 in the ninth over.
Barbados lost their last seven wickets for just 25 runs courtesy of Alana King who took 4-8 and McGrath 3-13. Ashleigh Gardener chipped in with a haul of 2-6 from her four overs as the batters fell like nine pins.
Spain are aiming to become the first side to win Olympic gold after lifting the Women's World Cup, having defeated England in the final of that tournament last year.
Ballon d'Or winner Bonmati levelled after Aoba Fujino's stunning 13th-minute free-kick opener in Nantes, before the Spain midfielder teed up Mariona Caldentey's winner 16 minutes from time.
That result saw Montserrat Tome's side seize top spot in Group C ahead of Brazil, who edged past Nigeria 1-0 thanks to Gabi Nunes' first-half finish.
Elsewhere in Group A, defending champions Canada put off-field issues to one side by overcoming New Zealand 2-1 thanks to goals from Cloe Lacasse and Evelyne Viens in Saint-Etienne.
Canada's integrity had been questioned ahead of the game in the wake of a spying scandal, with assistant Andy Spence serving as head coach after Bev Priestman volunteered to sit out.
Priestman, two members of her staff and the Canadian Olympic Committee are being investigated by FIFA's disciplinary committee after a drone was spotted flying over New Zealand's training on Monday.
"Obviously the timing was quite terrible," said Canada captain Jessie Fleming of the drone incident after her side battled back following Mackenzie Barry's early opener.
"But I think for us, we've just leaned into each other as a player group and we really just want to focus on being here and playing."
Hosts France seemed on course for a routine victory in the other Group A game after Marie-Antoinette Katoto's first-half double and Kadidiatou Diani's goal against Colombia.
However, Catalina Usme pulled one back from the spot and Manuela Pavi further reduced the deficit nine minutes later, only for Mayra Ramirez's late red card to help France hold out for a 3-2 victory.
Meanwhile, Germany swept aside Australia 3-0 in Group B, inflicting the Matildas' joint-heaviest defeat at the Olympics, along with a loss against the same opponent by the same scoreline, at Sydney 2000.
Efforts from Marina Hegering, Lea Schuller and Jule Brand sealed the victory for the DFB-Frauenteam against the Tokyo 2020 semi-finalists.
After being found guilty of using a drone to film opponents' training at this and past tournaments, the Tokyo champions had six points deducted, while head coach Bev Priestman has been banned from all football-related activity for one year.
The Canadian Soccer Association (CSA) are considering an appeal against the decision, but those controversies were put to one side when the team took to the field.
Starting the day bottom on -3 points, Canada, led by Andy Spence, had to come from behind to beat France after Marie-Antoinette Katoto put Les Bleues ahead just before half-time.
Jessie Fleming equalised from close range in the 58th minute, but Canada fought back, with Gilles getting some help from the woodwork to secure the win.
Meanwhile, Colombia's comfortable 2-0 victory over New Zealand means they now lead Group A after two games thanks to their goal difference.
Elsewhere, in Group C, Spain booked their place in the quarter-finals with a game to spare after a 1-0 win over Nigeria.
Alexia Putellas' long-range strike maintained La Roja's perfect start to the tournament as they bid to become the first team to win Olympic gold after lifting the Women's World Cup.
In the other group game, Japan ruined the party for Marta, who made her 200th appearance for Brazil in a shock 2-1 defeat.
Despite Mina Tanaka's penalty miss in the first half, Japan launched a comeback after Jheniffer's opener, with Saki Kumagai and Momoko Tanikawa both scoring in stoppage time to move second.
The game of the day came in Group B though, as Australia edged out Zambia in an 11-goal thriller.
Barbra Banda's hat-trick gave the minnows a 5-2 lead, but they could not hold onto it as Michelle Heyman made it 6-5 in the 90th minute to snatch a win.
Hayes, who took charge of the USWNT in May, has won six of her seven games at the helm, conceding just twice in that time.
The USA, along with Spain, are the only two sides to win all of their games at the Paris Olympics so far and will have great confidence heading into the knockout stages.
Trinity Rodman's second goal of the tournament two minutes from half-time sent them on their way, as Korbin Albert's 77th-minute strike saw her become the the youngest substitute scorer for the USA at the Olympics since Mallory Swanson against Colombia in 2016.
Alanna Kennedy's late strike would take some of the shine off an otherwise impressive display, but the United States dominated from the first whistle.
Hayes' side accumulated an expected goals (xG) of 2.82 from the 21 shots they had compared to Australia's 0.46, ending the match with 71.7% possession.
The United States will face Japan in the quarter-finals of the tournament, while Australia face a nervous wait to see if they qualify as one of the best third-placed teams.
In the other Group B encounter, Germany confirmed their place in the knockout stages alongside the United States following a comfortable 4-1 win over Zambia.
Lea Schuller opened the scoring in the 10th minute, with Klara Buhl adding the Germans second of the afternoon shortly after the restart.
Zambia captain Barbra Banda threatened to make the encounter a more difficult affair with her fourth goal of the tournament two minutes later.
But Schuller and Elisa Senß would add further gloss to the performance soon after to secure second place in the group.
Germany's triumph sets up a meeting with the runners-up of Group A, which could be either one of Colombia, France, Canada or New Zealand.
The Chelsea forward suffered the injury during a mid-season training camp in January, leaving her participation in serious doubt.
Kerr represented the Matildas at the 2016 and 2020 Olympics, also playing at four World Cups and four Asian Cups during her international career.
On Tuesday, Football Australia confirmed Kerr will not make the Olympic tournament – which begins on July 25 and ends on August 10 – while announcing the squad for two matches against China this month.
"Attacker Amy Sayer (ACL) and forward Sam Kerr (ACL) remain on the sidelines with long-term injuries," a statement from the governing body said.
"Kerr and Sayer will continue their rehabilitation programmes in their home club environments and subsequently will not be available for selection for the Paris 2024 Olympic Games."
Kerr, who is Australia's record scorer with 69 goals, was limited to just seven starts in the 2023-24 Women's Super League, contributing four goals and three assists for the eventual champions.
Australia's replies came from Sam Kerr, Caitlin Foord and Emily Gielnik in the seven-goal feast at Ibaraki Kashima Stadium.
It was 36-year-old Rapinoe and 39-year-old Lloyd who stole the show, though, on what may prove to be farewell appearances for the superstar duo.
Whether they play on in the short term for the national team remains to be seen, but this was likely a final outing at the Olympics for both, and they went out in style.
Rapinoe opened the scoring in the eighth minute when her wicked in-swinging corner from the left evaded everybody and found the net.
Kerr levelled seven minutes later with her 48th goal for Australia – a new national team record – when her shot proved too powerful for Adrianna Franch, but it was soon Rapinoe's time again.
The standout player from the 2019 World Cup smashed in her second goal of this game on the volley, connecting sweetly from around 12 yards after Alanna Kennedy sliced an attempted clearance.
Lloyd, who became the outright second most-capped player in US history by making her 312th appearance, got in on the goals just before half time. Her thumping left-footed shot across goal found the right corner, putting the US 3-1 up.
Lloyd scored again in the 51st minute after another Kennedy error, this time a weak header back to her goalkeeper allowing Lloyd a clear run on goal, with the striker slotting home.
That made her the US team's all-time highest scorer in Olympic women's football with 10 goals. Lloyd won Olympic gold in 2008 and 2012, with Rapinoe also on the triumphant latter team in London.
Australia got back into this game with a header from Foord after 54 minutes, and Kerr headed against the left post two minutes later. Substitute Gielnik rattled in a delicious late third for Australia, but they could not find a fourth.
Sweden had sensationally put an end to USA's 44-match unbeaten streak at the start of the women's tournament, with Megan Rapinoe admitting the beaten world champions had "played a bit tight" in a 3-0 defeat.
However, Vlatko Andonovski's side responded impressively to that setback on Saturday, thrashing New Zealand 6-1 in Saitama, in the process registering their largest margin of victory in an Olympics fixture.
Rose Lavelle and Lindsey Horan gave USA a 2-0 half-time lead, the latter on target to mark her 100th cap. Further efforts from Christen Press and Alex Morgan added to the score after the break, while they were helped out by their opponents scoring two own goals.
It is the Swedes who sit on top of the table, though, as a strong second-half performance sealed a 4-2 triumph against Australia.
Meanwhile, Banda equalled the record for most goals scored by a woman at a single Olympics, matching Christine Sinclair's tally of six for Canada at London 2012 with another treble, this time against China.
Zambia's captain scored all her country's goals in a 10-3 loss to the Netherlands in their Group F opener. She followed up with three more in a thrilling 4-4 draw on Saturday, though China's Wang Shuang went one better as she hit four in a see-saw contest.
Vivianne Miedema later moved level with Banda on six goals at this Olympics. The forward had scored four as the Dutch crushed Zambia, then managed another two in a 3-3 draw against Brazil.
Ellen White continued her impressive start to the tournament with the winner as Great Britain defeated hosts Japan 1-0 to qualify for the last eight.
Having scored twice in the opening 2-0 win over Chile, White made it 13 goals in her past 14 international outings when heading in a cross from Lucy Bronze in the 74th minute.
Also in Group E, Canada overcame Chile 2-1 thanks to a brace from Janine Beckie, putting them second in the standings ahead of a clash with Team GB to finish the round-robin stage.
USA - winners of the Olympic tournament four times previously - managed to beat the Netherlands 4-2 on penalties in their quarter-final after the game finished 2-2 at the end of extra time.
Having finished with fewer than six points in the group stage of a major event for the first time in their history, the USA knew a much-improved display was needed against a Dutch side who scored 21 times in their opening three games, the most of any women's side at a single Olympics.
They duly delivered a strong display as they twice took the lead only for Vivianne Miedema to continue her sensational form, scoring twice to cancel out goals from Samantha Mewis and Lynn Williams in an engrossing contest in Yokohama.
Megan Rapinoe swept the decisive penalty kick high into the net after Alyssa Naeher had made two stops to her right.
BRAZIL FALL SHORT AGAIN
Canada await USA after they inflicted further heartbreak on Brazil, whose wait for gold in this event goes on.
Beaten semi-finalists in Rio five years ago, Brazil were held to a 0-0 draw before suffering another defeat on penalties to the 2016 bronze medallists.
Goalkeeper Stephanie Labbe, who was injured in the closing stages of extra time, recovered to make two critical saves in the shoot-out to secure a 4-3 win.
"In the moment, it was about trusting myself, trusting my instincts, and trusting my ability to make a save," she said afterwards.
"Pain is temporary. We have our eyes on the prize."
WHITE TREBLE NOT ENOUGH AS MATILDAS WIN CLASSIC
The stand-out quarter-final took place between Australia and Great Britain, a seven-goal thriller eventually ending in a 4-3 victory for the Matildas.
Two goals from Ellen White had turned the game on its head and looked to be enough to send Hege Riise's side through, but Chelsea star Sam Kerr levelled in the 89th minute with a crisp low strike.
The contest then swung Australia's way in a dramatic minute in extra time, Mary Fowler's deflected shot finding the top corner after Caroline Weir had a penalty saved at the other end.
Kerr scored another before White completed her hat-trick with a deft header to set up a frantic finale, with Australia just holding on for a famous win.
Remarkably, they overperformed in terms of expected goals by 3.2, their highest such figure at these finals.
Australia will contest their semi-final against Sweden, who ended Japan's quest for a medal on home soil with a 3-1 victory.
Mina Tanaka cancelled out Magdalena Eriksson's sixth-minute opener, but Sweden took control in the second half through further goals from Stina Blackstenius and Kosovare Asllani.
USA bounced back from a shock 3-0 loss to Sweden in their opening game with a 6-1 win against New Zealand, but they dropped further points in the round-robin stage on Tuesday.
Previously unbeaten in 44 games before that Sweden loss, USA failed to break down Australia's defence – Alex Morgan's disallowed goal for offside the closest they came to doing so.
Mary Fowler hit the crossbar for Australia and in the end a point apiece was a fair outcome, with the Matildas also advancing to play Great Britain in the last eight.
It is the first time in history record four-time winners USWNT have finished with fewer than six points in the group stage of a major global tournament.
RAMPANT DUTCH AWAIT USA
Sweden were already assured of a place in the last eight ahead of their clash with New Zealand and saw the job through with a 2-0 win at Miyagi Stadium to finish ahead of USA.
Anna Anvegard and Madelen Janogy were on target for Sweden before half-time and they saw out a straightforward win that condemned New Zealand to a group-stage exit.
It means USA will now take on the Netherlands in the next round in what is a repeat of the 2019 Women's World Cup final. The Netherlands lost that match, but they enter this latest showdown in superb form after thrashing China 8-2 in Yokohama.
Lineth Beerensteyn, Lieke Martens and Vivianne Miedema all scored twice in the one-sided affair, while Shanice van de Sanden and Victoria Pelova were also on target.
The Netherlands' tally of 21 goals from three games is already the most scored by a team in a single women's football Olympics event, surpassing the USA's 16 from London 2012.
HOSTS JAPAN SCRAPE THROUGH
Japan did all that they could in the final round of group games by beating Chile 1-0 through a Mina Tanaka goal 13 minutes from time.
That win took the tournament hosts to four points from three games, enough to send them through as one of the best third-placed sides, along with Australia.
Already through to the quarter-finals, Great Britain snatched top spot with a late 1-1 draw against second-placed Canada in Tuesday's other Group E match.
Caroline Weir's long-range free-kick with 84 minutes played took a heavy deflection and cancelled out Adriana Leon's opener.
Brazil also booked their spot in the knockout stages thanks to Andressa's first-half free-kick in their 1-0 win against the tournament's lowest-ranked side in Zambia, who lost Lushomo Mweemba to an early red card.
The Selecao meet Canada in the quarters, while Australia await Great Britain.
