The Australian actress - who already picked up Best Actress at the BAFTAs, Screen Actors Guild and Golden Globe Awards for her role in 'Blue Jasmine' - is relieved awards season is over as being a favourite for the prizes was so uncomfortable.
Asked about the pressure of being frontrunner to take home the statue, she said: "It's an intense, unbearable pressure, which I'm so glad is over."
And Cate - who previously picked up Best Supporting Actress for her performance in 'The Aviator' in 2005 - admitted she has been "gobsmacked" by the performances of her fellow actresses, both this year and in recent times when she has been working in theatre away from Hollywood.
Speaking backstage at last night's ceremony, she told reporters: "Every year, I watch this thing remotely and there are five, six, 10, 20 performances by women that I am godsmacked by."
The 44-year-old beauty joked she had selected her ivory Armani gown after comparing it with others she was offered and asking "which one's the heaviest?"
She added: "I had the great good fortunate of being [a] princess this morning and have three dresses to choose from, and I chose this one."
And Cate had begun her preparations for the big day with an intense massage.
She said: "My morning began with being pummeled like Kobe beef. And it's just gotten better and better."
During her acceptance speech, the actress made a cryptic shout out to Julia Roberts, saying "Julia, hashtag suck it," and remained coy afterwards as to what she had meant.
She said only: "It happened in the bar with Ms. Roberts. And that's all I'm prepared to say."
