The actress has essayed the role fluidly despite its complexities, and Blanchett, in her acceptance speech said the film with "extraordinary screenplay", has been a "synthesis of my theatre work".
She acknowledged the work of all the best actress nominees this year - Amy Adams ('American Hustle'), Sandra Bullock ('Gravity'), Judi Dench ('Philomena') and Meryl Streep ('August: Osage County').
Apart from Dench, all the ladies were present at the dazzling gala, but Blanchett applauded the veteran for having a flourishing career even at the age of 78.
With seven Oscars including a history-making best director award for Alfonso Cuaron, the force of "Gravity" exerted itself at the 86th annual Academy Awards.