The women’s 200-meter backstroke has a new record-holder.

Seventeen-year-old American swimmer Regan Smith broke the record Friday with a time of 2:03.35 in a semifinal heat at the World Championships in South Korea. The previous record, of 2:04.06, was set at the 2012 London Olympics by Missy Franklin, the most decorated female swimmer in the history of the world championships. Franklin, who in 2012 also was 17, won the gold medal in the event en route to four golds that summer.

Smith’s historic heat was 3.22 seconds ahead of Canada’s Kylie Masse, who was the second-fastest qualifier. Smith broke her own junior world record in the preliminaries, finishing in 2:06.01.

Smith now holds the world, junior world, American and 17-18 age group national records. The final is scheduled for Saturday.

Also Friday, American Caeleb Dressel broke Michael Phelps’ record in the 100 butterfly. The 22-year-old won his heat in 49.50 seconds — 0.32 seconds better than Phelps’ mark set at the 2009 world meet in Rome at the height of the high-tech suit era.

“Just the standard that Michael set, wanted to go after it,” Dressel said. “I hope he was happy watching me do that.”

It was the second time this week a Phelps mark was broken at the worlds, with Hungarian Kristof Milak taking the 200 fly in 1:50:73, edging out the former record by .78 seconds.

With AP