Cooper Lutkenhaus, 16, set a world U18 record in the 800 meters with an electric stretch run at the U.S. Track & Field Championships in Eugene, Ore.

Cooper Lutkenhaus from Northwest High School in Justin stunned the track and field world on Sunday by setting a new under-18 world record.

Lutkenhaus, who just began running track three years ago according to Runner's World, finished second in the 800-meter with a scorching time of 1:42.27, shattering the world record for a runner under 18.

The United States, which had a frustrating swim world championships, ended on a high note Sunday with a world record in the women’s 4x100 medley in the last event of the eight-day championships.

The U.S. women's 4x100 medley relay team of Gretchen Walsh, Regan Smith, Kate Douglas and Torri Huske set a world record at the swimming world championships, while Summer McIntosh and Leon Marchand both picked up another gold.

The United States set the world record in the women's 4x100 metres medley relay at the world championships in Singapore on Sunday.