Katie Ledecky faces a task seemingly tailor-made to accentuate her freestyle swimming greatness on Day 4 of action from the Tokyo Aquatics Center.
In the span of a little over an hour, Ledecky will race the finals of both the women's 200m freestyle and women's 1500m freestyle. The latter of which is taking place for the first time as an Olympic event.
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Others in action include Caeleb Dressel in the semifinals of the men's 100m freestyle and Kristof Milak in his signature men's 200m butterfly.
Watch the action LIVE in primetime on NBC beginning at 9:30 p.m. ET and stream the entire session LIVE on NBCOlympics.com and the NBC Sports app.
Follow along below for live updates, results and highlights as things unfold.
Men's 100m Freestyle - Semifinals
Caeleb Dressel won the first heat in a comfortable 47.23, likely conserving energy for the event final.
"I can still clean a lot up, but I'm happy with that," a relaxed Dressel said after. He assured there was still plenty left to give in the final.
It did not stand up as the best time, however. Russian athlete Kliment Kolesnikov – already a silver medalist at these Olympics – won the second heat 0.12 faster than Dressel.
American Zach Apple finished 11th overall and did not advance.
SEE MORE: USA's Dressel shuts it down in 100m freestyle semifinal win
Women's 200m Freestyle - Final
Breakout Australian swimming star Ariarne Titmus backed up her 400m freestyle victory with another gold medal performance in a field that included Katie Ledecky, winning the 200m freestyle in an Olympic record 1:53.50.
Hong Kong's Siobhan Haughey, who led Titmus by a half-second at the 150 mark, took silver.
Titmus closed with a final split of 28.8 to pass Haughey with 15 meters to go.
Canada's Penny Oleksiak, a Rio 2016 gold medalist in the 100 free, took bronze as Katie Ledecky, never seeming to be in contention for the win, finished fifth.
SEE MORE: Ariarne Titmus closes for dramatic 200 free win, Ledecky 5th
Men's 200m butterfly - Final
Hungary's Kristof Milak was unable to beat his own world record in the men's 200m butterfly, but he did manage to set an Olympic record in 1:51:25.
Japan's Honda Tomoru won the host nation's second swimming medal of the Tokyo Games with silver in 1:53.73, followed by Italy's Federico Burdisso.
Chad Le Clos led after 100m but faded to fifth.
American Gunnar Bentz finished seventh in what he said on social media would be the final race of his career.
SEE MORE: Hungary's Kristof Milak dominates field for 200 fly win, OR
Women's 200m butterfly - semifinals
Americans Regan Smith and Hali Flickinger went 1-2 in the first semifinal, advancing comfortably. Flickinger's time of 2:06.23 topped the heat.
Chinese swimmers Zhang Yufei blew that time away in the second semifinal, though, advancing in 2:04.89
SEE MORE: Hali Flickinger, Regan Smith advance to 200 fly final
Men's 200m breaststroke - semifinals
Nic Fink is into the final of the 200 breast behind medal contenders Zac Stubblety-Cook and James Wilby. Fink finished second in a slow first heat at 2:08 flat.
Anton Chupkov, the 2016 gold medalist and world record holder, only managed a seventh place qualification but will still be a contender for gold in the final.
SEE MORE: Nic Fink makes 200m breaststroke final in 2:08 flat
Women's 200m IM - final
A thrilling final came down to the freestyle sprint in the final 50, which went the way of Japanese swimmer Ohashi Yui in 2:08.52, beating out Americans Alex Walsh and Kate Douglass, who rounded out the podium.
Ohashi completed the sweep of the women's individual medley events. The events have been swept by the same swimmer at every Olympics since 1996. The last to do it, Hungary's Katinka Hosszu , also raced in this final, finishing seventh nearly four seconds back.
Women's 1500m freestyle - final
Prepare for 15 minutes of smooth, emphatic dominance as Ledecky races her strongest event.
At world championships and U.S. Trials, Ledecky has demonstrated that she can still crush the field in the 1500 by several seconds even after competing in the 200 free in the same night.
The race for silver could come town to the other American in the race, Erica Sullivan, against Chinese distance specialist Wang Jianjiahe.
Men's 4x200m Freestyle - final
Great Britain and Australia are the favorites in the 800 relay as the United States clings to an outside shot at a medal.