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Hungarian swimmer Kristof Milak won the 200-metre butterfly at the World Swimming Championships on Wednesday, breaking Michael Phelps' world record in the process.

The 19-year-old produced an astounding performance to take gold in one minute, 50.73 seconds, beating Phelps' benchmark by an impressive 0.78 seconds:

South African Chad le Clos set an early pace in the final, leaving the competitors under world-record pace at the halfway mark. However, the Hungarian blew away the rest of the field in the second half of the race.

Milak's nearest competitor was Japan's Daiya Seto (1:53.86), while Le Clos did enough to take third (1:54.15).

On his Instagram account, Phelps shared part of a phone conversation he had with the teenager: "It happened because there was a kid who wanted to do it, who dreamed of doing it, who figured out what it would take to do it, who worked on his technique until it was beautiful and who put in the really, really hard work that it takes to do it."

Former Olympic gold medalist Cameron van der Burgh was impressed with Milak's performance:

Phelps set his most recent world record at the 2009 world championships in Rome. Pat Forde of Yahoo put into context for just how long the American was at the summit of the 200-metre butterfly:

Phelps retired from swimming following the 2016 Olympics in Rio de Janeiro. He is the most decorated Olympian of all time, having won 28 medals in total at the Games, 23 of which were gold.

Milak was crowned European champion a year ago, but the world record stands as his finest career achievement to date.

All eyes will be on the Hungarian on Friday, when he will be in action in the heats of the 100-metre butterfly event ahead of Saturday's final.