The 31-year-old model - who is partnered alongside professional dancer Dmitry Chaplin - had to fight back tears as she discovered she had been eliminated from the competition after coming joint bottom of the leaderboard the previous evening.
Despite former Playboy model Kendra Wilkinson and actor Ralph Macchio receiving equally poor scores for their routines, the Czech beauty was joined in the bottom three by former 'Cheers' star Kirstie Alley - who had enlisted the services of John Travolta to help her with her moves - and wrestler Chris Jericho.
Although visibly upset to be leaving the show, Petra admitted the time she had spent on 'Dancing with the Stars' had been "life-changing".
After expressing his distaste at the line-up of the bottom three, claiming neither Petra, Kirstie nor Chris should have been battling to stay in the competition, head judge Len Goodman said Petra had been "fantastic".
He said: "No wonder I get grumpy. Neither of these deserves to be there. Not one of them deserves to go home. And yet there they are.
"Petra's been fantastic. Two weeks ago she was leading the top of the leader board, Chris did the best dance of his life last night. It's Madness."