The Sixers allrounder struck 136 from 108 balls at Manuka Oval, Canberra, including seven sixes, breaking the record for the most sixes in a WNCL innings.
It was also the seventh highest score by a Breaker in WNCL history. Sixers wicketkeeper-batter Alyssa Healy holds the record of 159 from 116 deliveries posted in 2016/17 against Tasmania.
Gardner followed her century with 3-37 from 10 overs. Her off-spin helping dismiss Queensland for 225 chasing 249 for victory.
The 22-year-old was one of four Sixers recently selected in the Australian Women’s T20 World Cup squad along with Healy, Sixers WBBL captain Ellyse Perry and allrounder Erin Burns.