Katie Ledecky is very fast. Although she couldn’t outpace the Australians as the anchor in the 4×100 relay on Saturday, Ledecky paced herself well on Sunday in the 400-meter freestyle, just missing her own world record and setting an Olympic record with her 3:58.71 time.

When she found out after the race how close she was to breaking the world record, the young American was incredibly hard on herself.

“My last stroke was a little lackadaisical. I shouldn’t have done that. I’ll be fine tonight,” Ledecky said.

I wish one day when I do something lackadaisical, I nearly set a world record. The 400-meter freestyle is set for Sunday night at 10:01 p.m. If Ledecky follows through on her promise, we’ll see another world record fall tonight.

She also seemed pretty pleased with herself after the first heat.

USATSI