Three junior world records fell on day two of the International Swimming Federation World Junior Championships in Indianapolis.
Russia's Ivan Girev clocked 1min 46.40sec en-route to gold in the men's 200 metres freestyle at the Indiana University Natatorium.
That beat the mark previously held by American Maxime Rooney by .70 seconds.
Nandor Nemeth of Hungary was timed at 1:46.79 for silver as Elijia Winnington of Australia finished third to earn bronze in 1:46.81.
A second junior world record fell in the women's 100m backstroke as Regan Smith impressed in front of her home crowd.
The American clocked 59.11 to win gold to beat a mark previously held by Canada's Taylor Ruck, who was second today in 59.23 and had clocked a world record 59.28 in the semi-finals.
Bronze went to another Canadian, Jade Hannah, who was timed at 59.62.
"Setting the world junior record was insane," said Smith.
Germany's Johannes Hintze was also in world record form as he won the men's 200m individual medley.
He was timed at 1:59.03 to fend off the challenge of home hope Kieran Smith, the silver medallist in 1:59.56.
Bronze went to Marton Barta of Hungary in 2:00.14.
Nicolo Martinenghi of Italy was not able to improve on the junior world record he set in the semi-finals, but he still won gold.
The Italian champion's winning time, 59.58, was one-half second faster than silver medallist Reece Whitley of the US.
Another American, Michael Andrew, finished in 1:00.37 to win bronze.