The 23-year-old Olympic 100m butterfly champion touched in 24.84sec with Gabi Albiero of the United States and both were awarded gold.

It meant no silver medal was awarded as Catie DeLoof of the US took bronze.

MacNeil had already won the 100m freestyle, 100m butterfly and 4x100m freestyle relay titles at the Aquatic Center Laguna Los Morros.

"This race is a very short race, so I was happy to arrive first with Gabi," said MacNeil.

"It was very exciting. 

"Obviously I made some big mistakes, but I'm really excited. 

"This tie thing happened to me once in the 50m at the Short Course Worlds in Melbourne in 2022."

Albiero added: "Maggie is one of the most awarded swimmers and she is very consistent, so to be able to be on the podium with her is a great moment and I am very proud of myself and her."

Elsewhere, American Paige Madden and Brazilian Guilherme Costa each won their third gold medals of the Games with relay success.

Madden was part of the US line-up which won the 4x200m freestyle title in 7min 55.26sec.

She added to her individual titles at Santiago 2023 in the 400m and 800m freestyle.

Costa helped guide Brazil to the men's 4x200m freestyle crown in a Games record 7:07.53, after also earlier winning over 400m and 800m.

Canada's Julie Brousseau won her second gold of the Games as she claimed the women's 400m individual medley title in 4:43.76.

Brousseau had previously been part of her country's winning 4x100m freestyle squad.

There was victory for the US in the men's 50m freestyle as David Curtiss touched first in 21.85.

His team-mate Jay Litherland won the men's 400m individual medley final in 4:15.44. 

Swimming at Santiago 2023 is due to conclude tomorrow.