The Sochi Olympian finished her first final for the year in a time of 1:30.679. Race winner, Marianne St-Gelais of Canada finished in a time of 1:29.496.
A restart of Lockett's quarterfinal was triggered after two competitors fell on the way to the finish-line but the 21-year-old maintained composure to win the restaged race.
“I am really pleased with my result, but having to re-skate the quarterfinal really hurt my legs,” Lockett said. “Without the rerun I may not have advanced through.”
Lockett booked a start in the decider after finishing second in her semi-final.
“I am feeling strong, but I just need to work at getting off the line better in the shorter distances to improve my tactical positions when racing, but overall I am really happy with my results today and I’m looking forward to the 1,500m semi-final," she said.
Live streaming of Sunday's competition is available through the ISU website.