Caeleb Dressel triumphed over rival Kyle Chalmers in one of the best races of Tokyo 2020, while China pulled off an upset to win an incredible women's 4x200m freestyle race in a world-record time.

Dressel was one of three competitors to set new Olympic benchmarks in the individual races at the Tokyo Aquatics Centre on Thursday, with Zhang Yufei and Zac Stubblety-Cook also doing so en route to winning gold.

There was glory for Dressel's United States team-mate in the men's 800m freestyle, too, where Bobby Finke topped the podium.

Here is a recap of all the goings-on from another enthralling session at the pool.

DRESSEL EDGES CHALMERS IN THRILLERS

Earlier this week, it was Australia beating the US in one of the races of the meet when Ariarne Titmus held off Katie Ledecky in the 400m free.

This time it was glory for Team USA as Dressel won his second gold of the Games in an awesome 100m free final, with Australia's defending champion Chalmers just 0.10 seconds behind.

These two had battled before, with Chalmers entering the Games with two victories to one over the past five years, and the duo delivered an enthralling battle down the stretch.

But it was Dressel, part of the US team that won the 4x100m free relay earlier this week, who touched home in an Olympic record of 47.02 seconds.


TITMUS, LEDECKY BEATEN AS CHINA PULL OFF WR

Titmus has been one of the stars of these Games, pulling off a 200m and 400m free double. She and her previous record-holding Australia team-mates were favourites for gold in the 4x200m relay but had to settle for third in a race where each of the top three went under the previous world record time.

It was the foursome from China that pulled off the big win, leading from the first leg and holding on despite a frantic finish in which Ledecky so nearly anchored the United States to first place.

Ledecky fell narrowly short, though, as the US quartet took silver.


FINKE'S FINAL FLURRY

The opening race of the day produced a thrilling finish in the first men's 800m freestyle Olympics final, with Finke taking gold after turning on the jets late on.

Finke was seemingly not in contention after turning for the final 100m down in fifth and was still behind Germany's Florian Wellbrock, Italy's Gregorio Paltrinieri and Ukraine's Mykhailo Romanchuk on the turn for home.

But a sensational 26.39 split down the final stretch completed a stunning comeback to take gold for the United States ahead of Paltrinieri and Romanchuk.


NEW OLYMPIC RECORDS FOR ZHANG AND STUBBLETY-COOK

China's Zhang swam the third fastest time ever to take a dominant gold for China in the women's 200m butterfly.

Zhang hit the front early and never looked troubled en route to touching home first in a time of 2:03.86, a new Olympic record.

American duo Regan Smith and Hali Flickinger were second and third. Since 2012, the United States had landed a medal in every pool event bar the women's 200m butterfly, with this ending the longest medal drought in US swimming.

Stubblety-Cook took out the men's 200m breaststroke final thanks to a barnstorming last 50m.

The Australian moved into the top three at the 150m mark and powered home in a time of 2:06.38, beating Arno Kamminga and Matti Mattsson to top spot.