Another great day in the pool saw Team GB and the Russian Olympic Committee secure one-twos, while teenager Lydia Jacoby earned a surprise triumph and Kaylee McKeown brought home another swimming gold for Australia.
There was also a further look at Ariarne Titmus and Katie Ledecky at the Tokyo Aquatics Centre, with the pair securing their passage to the final of the women's 200 metres freestyle.
Here is a round-up of Tuesday's goings-on in swimming at the Olympics.
MORE AUSSIE SUCCESS AS MCKEOWN SETS NEW OLYMPIC MARK
Just a day on from Titmus' thrilling win over Ledecky in the 400m freestyle, Australia had more reason to celebrate in the pool on Tuesday as McKeown won the 100m backstroke, becoming the first Australian woman to triumph in the event.
Her time of 57.47 seconds established a new Olympic record, the fourth time this week in the event a new benchmark has been set, and was only 0.02 seconds off her own world-record time.
Kylie Masse had led at the 50m mark and the Canadian held off the challenge of Team USA's Regan Smith to take silver.
GOLD FOR KAYLEE MCKEOWN— Australian Swim Team (@DolphinsAUS) July 27, 2021
Kaylee set the pool alight with an exceptional swim in the 100m back touching in 57.47
She becomes the nation's golden girl - being the first Australian female to win gold in the event
#TokyoTogether | #Tokyo2020 | #Swimming | @AUSOlympicTeam pic.twitter.com/lhJumXHmrK
DEAN PIPS SCOTT AS GB GO ONE-TWO
A thriller in the men's 200m freestyle saw Tom Dean pip Duncan Scott to gold as two British male swimmers stood on the same Olympic podium for the first time since 1908.
Scott was fastest in Monday's semi-finals and a blistering finish put him right in contention, but it was Dean, having made a superb opening, who just touched home first by four hundredths of a second.
"I knew it was going to be a dog fight," Dean, whose time of 1:44.22 is a new British record, told BBC Sport.
"I didn't know how people were going to swim it. It was just race to race."
TEENAGE KICKS AS JACOBY UPSETS THE ODDS
The shock of the session came in the women's 100m backstroke where American world-record holder Lilly King and Olympic benchmark setter Tatjana Schoenmaker of South Africa were favourites for gold.
There was an American winner but it was not King, the honour instead going to 17-year-old Jacoby, who became only the sixth swimmer to break 1:05.
The teenager broke free in the final 20m and defending champion King was proud of her younger team-mate's phenomenal achievement.
"We love to keep that gold in the USA family so this kid just had the swim of her life and I'm so proud to be her team-mate. I'm proud to get bronze for my country," King said.
RUSSIAN DUO BEAT MURPHY IN 100 BACK
Defending champion and world-record holder Ryan Murphy had to settle for bronze in a lightning 100m men's backstroke final, which saw the Russian Olympic Committee secure a one-two.
Evgeny Rylov (51.98), the 200m back world champion, edged compatriot Kliment Kolesnikov (52.00) in a tight finish as the USA did not win either gold or silver in this race for the first time since 1980 – when they boycotted the Games.
TITMUS AND LEDECKY TO BATTLE AGAIN?
If Monday's 400m clash was anything to go by then we could be in for another treat at the pool on Wednesday. Titmus qualified fastest in the women's 200m freestyle, with Ledecky winning her heat and going through third quickest overall.
Kristof Milak, who owns the world record, swam fastest in the men's semi-finals for the men's 200m butterfly, while Kate Douglass was quickest in the semis for the women's 200m individual medley.