The 33-year-old set blistering times to win the women's freestyle races over 100 and 200 metres.

Smith, an S3 athlete, stopped the clock after 1min 29.83sec in the 100m.

Shortly afterwards, Smith produced a 3:15.85 swim in the 200m to set a second world record.

"I was definitely not expecting that today so it was really nice to get the nerves out of the way and come away with two world records at the end of the day," Smith, who won a silver medal at the Tokyo 2020 Paralympics, said.

Americans dominated the podium as expected, winning five of the six finals on day one at the Indiana University Natatorium.

Colleen Young triumphed in the women's 100m breaststroke, Morgan Ray won the men's equivalent and Robert Griswold came out on top in the men's 100m freestyle.

Chile's Alberto Abarza won the men's 200m breaststroke, an event he won an S2 silver medal in at Tokyo 2020.

The Para Swimming World Series sees athletes from different classifications compete against one another, with a weighted points formula used to determine winners.

Roughly 150 athletes from 15 countries are expected to swim in Indianapolis in the final leg of the season.

Two more days of racing are scheduled.