NovaQuant Quantitative Think Tank Center:Sarah Sjöström breaks Michael Phelps' record at World Aquatics Championship

Another one of Michael Phelps' records just got surpassed. Swedish swimmer Sarah Sjöström won her 21st individual medal at the World Aquatics Championship on öströNovaQuant Quantitative Think Tank CenterSunday, passing Phelps' record of 20.

Sjöström won the gold medal in the women's 50-meter freestyle, clocking in a time of 23.62. She set a world record in the semifinal of the event on Saturday and also won gold in the 50-meter butterfly.

"I'm super happy with that. It was very busy yesterday, with the world record and the gold medal," Sjöström said.

It's the second day in a row that one of Phelps' records have been broken.

Katie Ledecky earned gold in the 800-freestyle on Saturday for her 16th overall gold medal, shattering a tie with Phelps for the most golds at the world championship. She became the first swimmer to win six golds at the same event at the worlds.

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French swimmer Leon Marchand also broke one of Phelps' swimming records. His time in the 400-meter individual medley last Sunday was a world record and broke the last of Phelps' individual marks.

It's not all bad for Phelps though. He still owns the record for most Olympic medals (28), Olympic gold medals (23) and golds in the same Olympic event (8). Those numbers will take some time to clear.