Generational swimming talents Summer McIntosh and Katie Ledecky clash in Olympics preview

In one of the most consequential non-Olympic races in years, all-time swimming great Katie Ledecky could face an unprecedented challenge Saturday from Canadian teen Summer McIntosh in an event the American has owned for more than a decade.

The pair will compete in the 800-meter freestyle final of the swimming world championships, in a race that’ll be streamed live on Peacock at 8:21 p.m. local time in Singapore (8:21 a.m. ET)

“This will be the biggest race of this century, men or women, from outside of the Olympic format,” three-time gold medalist and NBC swimming analyst Rowdy Gaines told NBC News. “I don’t know how you can get bigger than this.”

Gaines called the Ledecky the greatest female swimmer of all-time and McIntosh the best contemporary performer, saying both judgments are “not even close.”

The 28-year-old Ledecky has 14 Olympic medals on her mantle at home, nine of them colored gold. McIntosh, 18, took home three golds and a silver from in Paris last year.

“Katie is the greatest of all time, absolutely, and it’s not even close,” Gaines said. “(McIntosh) is world swimmer of the year at the end of the year, regardless of what happens in the 800 (on Saturday). She’s still the world swimmer of the year by far, nobody’s even close.”

Both swimmers cruised through their qualifying heats Friday afternoon to formally qualify for Saturday’s final.

Ledecky will be in Lane 4 on Saturday, with McIntosh in 3 and Australia’s Lani Pallister in 5.

The grind of this long meet doesn’t seem to be bothering McIntosh.

“Honestly, I felt a lot better than I thought I was going to this morning,” she said after her 800 heat. “I’ve been recovering really well. I mean, we’re on Day 6? So I feel like this really promising.”

On the line in this millennial vs. Gen Z battle is Ledecky’s death grip on the 800 free. Her domination of the race predates former Canadian Prime Minister Justin Trudeau’s recent residency at 24 Sussex and former White House occupant Barack Obama’s second term.

The Maryland native and niece of New York Islanders co-owner Jon Ledecky took 800 gold at the 2012 Olympics in London, 2016 in Rio, 2021 in Tokyo and last summer near Paris.

She’s the only woman to win the same individual event at four Olympics, in any sport. The only other swimmer to pull off such a four-peat was American legend Michael Phelps, who took the 200 individual medley in 2004, 2008, 2012 and 2016.

Ledecky has also won the 800 free six consecutive times at the world championships dating back to 2013.

But Ledecky’s air of 800 invincibility was dented last year when McIntosh, then just 17 years old, touched the wall first at at the Southern Zone South Sectional Championships in Orlando, Florida, on Feb. 8.

McIntosh opted against swimming in the 800 in France to concentrate on other events as she took gold in 200 butterfly, 200 Individual Medley and 400 Individual Medley to become one of the breakout stars of last summer.

The Toronto native and daughter of 1984 Canadian Olympic swimmer Jill Horstead is committed to swimming the 800 in Los Angeles and Saturday’s splash against Ledecky could serve as a tantalizing preview of that potential Olympics clash.

Ledecky has shown no signs of slowing down. Earlier this week, she scooped up gold in the 1,500 free and a bronze in the 400 free won by McIntosh.

The Canadian has already bagged three world golds this week in that 400 free, 200 IM and 200 fly.