Their Jamaican shooter Romelda Aiken scored 11 from 12 attempts while her compatriot Carla Borrego began slowly for Adelaide.
Borrego was initially well-held by Firebirds captain Laura Geitz, forcing the T'birds to rely largely on Bell as a scoring avenue.
Queensland held their four-goal buffer until their wing defence Gabrielle Simpson turned an ankle, which turned the tide of the game.
Simpson called an injury time-out with 13 minutes remaining in the second term.
On resumption, the Thunderbirds scored nine of the next 13 goals to steal momentum and take a 24-23 advantage into halftime.
Adelaide's revival coincided with Borrego breaking Geitz's shackles and, finding top gear to finish the opening half with 15 goals from 17 attempts.
The Thunderbirds then scored 16 goals to 11 for a what appeared a commanding five-goal lead at the last change - however the Firebirds rallied and reduced the deficit to one goal with 10 minutes remaining.
A tense period followed with the Queenslanders still just one down with 50 seconds to play.
But Adelaide controlled the ball before Bell deservedly iced the title with a long range attempt.
