There aren't enough superlatives to describe Katie Ledecky's freestyle dominance at the World Swimming Championships, and for superstar Michael Phelps no words at all to describe the struggles of the rest of the US team.

The 18-year-old Ledecky’s three victories have accounted for all of the US gold through four days of competition in the pool.

With her 200M free triumph on Wednesday treble world record-holder Ledecky proved herself not only a distance great but a freestyle phenomenon. "Otherworldly" was the word Phelps's coach Bob Bowman used to describe Ledecky, who added the 200M free to her 400M and 1500M victories.

She can become the first swimmer to sweep four freestyle world titles from 200M-1,500M with a win in the 800M free. "She's doing what you have to do at that level and that's continuously get better," Bowman said. "She's done that since 2012, not only leading up to 2012, she didn't miss a beat. She's just continually prepared and improved. That's what it takes to do stuff like that."

Phelps -- trying to extend a glittering Olympic career that reached its zenith with his record eight gold medals in Beijing in 2008 -- said he remembers what it's like to dominate as Ledecky does. "A long time ago, but been there," he said, drawing a laugh. "She wants it. She's hungry. It's good to see her just continually dominating."