PARIS — Australia topped a Katie Ledecky-led Team USA to gold in the women’s 4x200-meter freestyle relay here on Thursday, and set the stage for a broader head-to-head battle over the final three days of the 2024 Olympic swimming competition.

The U.S. took silver — Ledecky's 13th at the Olympics, the most ever won by an American woman. But she, Claire Weinstein, Paige Madden and Erin Gemmell were no match for the vaunted Aussie foursome: Olympic champion Mollie O'Callaghan, Lani Pallister, Brianna Throssell and world record holder Ariarne Titmus.

The relay victory left Australia atop the meet’s gold-medal table, with five to Team USA’s four.

And while the U.S. has more upside across the 11 finals that remain, a decades-long run of dominance in Olympic swimming seems to be in danger.

The first two-thirds of the meet have fallen short of American expectations. They have produced plenty of medals — 19 in total. But most gold medal threats have fallen short of the top step of the podium.

Ryan Murphy, for example, took silver in the 100-meter backstroke, then failed to make the final of the 200. Bobby Finke finished second in the 800-meter freestyle, a race he won in Tokyo three years earlier. Neither Chris Guiliano nor Jack Alexy came close to sprint freestyle medals. And the men’s 4x200 relay came second to Great Britain.

On the women’s side, the 4x100 relay team also came up short against Australia. Regan Smith lost her first of two backstroke duels with Australia’s Kaylee McKeown, and settled for silver again in the 200. Lilly King finished fourth in the 100 breast by 0.01 seconds.

Others — like Torri Huske in the 100 free, or Nic Fink in the men’s 100 breast, or Luke Hobson in the men’s 200 free — have exceeded expectations, but their medals have been silver or bronze.

The only golds have come from Huske, Ledecky, Kate Douglass and the men's 4x100 relay on opening night.

The final weekend of competition will pack plenty of medal potential for both the U.S. and Australia.

Possibly pivotal events include:

Friday’s women’s 200 backstroke, Part II of Smith vs. McKeown

Friday’s men’s 50 free, in which Australia’s Cam McEvoy is the favorite and Team USA’s Caeleb Dressel is a contender

Saturday’s women’s 200 IM, in which McKeown and Douglass are both contenders

Saturday’s women’s 800 free, in which Ledecky is a clear favorite, but Australia’s Ariarne Titmus could challenge her

All three medley relays (Saturday and Sunday)

The last time the U.S. did not win the most swimming gold medals at an Olympics was 1988 (to East Germany).

The last time the U.S. lost to a team not widely suspected of doping was 1956 (to Australia).