She advanced to the super final of four in second and attempted a quad jump with a 4.425 degree of difficulty. A dodgy landing meant she scored 72.12.
The gold went to Belarus’s 34-year-old veteran Alla Tsuper with 98.01 and Mengtao Xu of China won silver with 83.50.
Favourite Li Nina of China came fourth after falling in the final.
“I was always going to go into these Olympics with that approach, all or nothing,” Lassila told Channel 10.
“I didn’t have the easiest of days but I made it through each round.
“I’m very happy with my performance. It would have been great to land that jump but… I just couldn’t get there.”
Lassila’s bronze is Australia’s second medal in Sochi, following Torah Bright’s silver in the snowboarding halfpipe.
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