Janet Evans, a 15-year-old from Placentia, Calif.,...

Janet Evans, a 15-year-old from Placentia, Calif., and Poland’s Mariusz Podkoscielny won the grueling 1,000-yard freestyle events in the opening day of the U.S. Swimming Short Course National Championships at Boca Raton, Fla.

The two distance events were the only ones contested in the first day of the five-day competition at the Mission Bay Aquatics Center.

Swimming experts claim Evans, who is 5 feet 3 inches and 90 pounds, is the smallest U.S. swimming champion ever.

Evans went the distance in 9:32.59 to easily beat Kim Brown of Irvine, who was second in 9:36.55. Debbie Babashoff of Mission Viejo was third in 9:39.43.

Podkoscielny finished in 8:54.93 to beat Alex Kostich of Belmont, Mass., in the men’s event. Podkoscielny, a native of Gdansk, is allowed to compete in this event because he lives and trains in Mission Viejo.

Kostich was timed in 8:56.18, with Luis Morell of Boca Raton next at 8:57.89 and another Pole, Tomasz Gawronski, fourth at 8:58.13.