ICYMI: Gymnastics upset, Katie Ledecky grabs silver, Caeleb Dressel takes gold and more updates from the Tokyo Olympics

In the latest installment of Tokyo Olympics action, Australian superstar Ariarne Titmus upset Katie Ledecky in the 400-meter free -- which was seen as Ledecky's toughest race -- and men's swimmer Caeleb Dressel earned his first gold medal of the Games, in the 4x100 relay.

Women's skateboarding was also awarded its first-ever Olympic gold. Meanwhile, U.S. softball defeated Japan in a preview of what could be to come in the gold-medal game later this week when the two teams face off again. And in the early hours of Monday morning, the U.S. men's gymnastics team attempted an upset of its own: After a fourth-place finish in qualifications, the Americans aimed for the podium in team finals.

We've got you covered with all the action you might have missed:

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Upset in men's gymnastics

The Russian Olympic Committee team edged home team Japan for gold by just a little over a tenth of a point. And it came down to ROC's Nikita Nagorny on the very last routine. The 2019 world all-around champion saved an early pass from going out of bounds, then stuck his half-in half-out dismount on floor to clinch the win. The U.S. team, led by Sam Mikulak's parallel bar score of 15.000, placed fifth, one spot below its finish in prelims.

Titmus dethrones Ledecky

The highly anticipated showdown between Australia's Ariarne Titmus and five-time Olympic gold medalist Katie Ledecky ended in the slimmest of margins. Ledecky swam her second-fastest time of her career, 3:57.36 -- behind only the world and Olympic record she set at the Rio Olympics -- and still lost to Titmus, who came in at 3:56.69. Her silver medal finish marked the first time Ledecky has not won gold in an Olympic individual event.

As Titmus touched the wall, her coach was thrilled -- to say the least.

Ledecky had to turn around quickly for her 200-meter heat and set an Olympic record for the 1,500-meters.

She will race for gold in the event Tuesday night.

Brazil's top cheerleader

Dani Alves, 38, is one of Brazil's most famous footballers and has enjoyed a remarkable career at the top of the sport. Now, he is using his social media platforms with a combined 47 million followers to call for greater support for the country's athletes at Tokyo 2020.

If his social media accounts are to be believed, Alves, who captained Brazil to a 4-2 win over Germany in its Tokyo 2020 pool stage opener on Thursday, is loving life in the Olympic Village. He was inspired by 13-year-old skateboarder Rayssa Leal's silver medal and sent her a message of congratulations via Instagram, but he also used the platform to call for further investment in Brazil's athletes.

"I take advantage of this beautiful image [Rayssa Leal skating her way to the podium] to raise my voice in support of Brazilian sport," his post said. "We need to invest more in our sports and our athletes.

"You can't always win on courage alone, but if that's the way it has to be, then we're all in, body and soul. Congratulations to little giant @rayssalealsk8 for her great performance and for being such an example to our young people.

"And I'm not here for the applause.... I will applaud all the athletes who are here representing our nation and our people with great honour and love for our country!!"

-- Tom Hamilton

And here's Leal crushing it as a 7-year-old.

A loss, then a proposal

For Argentine fencer Maria Belen Perez Maurice, the sting of Olympic defeat was quickly parried by a stroke of love.

Perez Maurice had just been beaten in the women's saber when her longtime coach and partner Lucas Guillermo Saucedo turned the loss into a surprise marriage proposal.

While Perez Maurice was speaking to reporters, Saucedo held up a handwritten note asking "Do you want to marry me?" in Spanish. She accepted.

Dressel and U.S. men's relay team win gold

Caeleb Dressel gave the U.S. an early lead in the 4x100-meter freestyle relay. Italy won silver, while Australia snatched bronze.

One former swimmer you might have heard of was impressed ...

Read more: Dressel is ready for his star turn

Elsewhere in the pool ...

Regan Smith set an Olympic record in the women's 100-meter backstroke during her semifinal heat.

Skates like teen spirit

Japan swept street skateboarding's Olympic debut. With her win, 13-year-old Momiji Nishiya of Osaka became the fifth-youngest gold medalist in Olympic history. Brazilian Rayssa Leal, who is also 13, took silver, and 16-year-old Funa Nakayama of Toyama, Japan, took bronze. The future of women's street skating is bright.

What were you doing at 13?

Alexis Sablone, 34, a three-time X Games gold medalist with a master's degree in architecture from MIT, was the only American in the final and finished just off the medal podium in fourth. -- Alyssa Roenigk

Surfing USA

In a duel between American surfers, California's Kolohe Andino eliminated Hawaii's John John Florence to advance to the quarterfinal. The two shared a nice moment in between heats.

Osaka cruises into third round

Four-time Grand Slam champ Naomi Osaka of Japan needed just 65 minutes to see off 49th-ranked Viktorija Golubic of Switzerland to reach the last 16.

And the crowd goes wild!

Despite failing to manage a hit for the first five innings, Team USA softball tied Japan in the sixth inning and won 2-1 in the seventh, thanks to a walk-off home run off Kelsey Stewart's bat. The same two teams, which were undefeated headed into Sunday's game, will meet in the gold-medal game scheduled for Tuesday evening Tokyo time. Cue: pandemonium.

Moves like Jagger

When summer meets winter ...

Doncic puts on a show

A debut to remember -- for both player and country. Luka Doncic led Slovenia to a blowout win over Argentina, 118-100, in the nation's first appearance in Olympic basketball. The NBA star ended the game with 48 points, 11 rebounds and 5 assists -- the first player to score more than 40 points at the Olympics since Brazil's Oscar Schmidt in 1996.