"I was thinking about the beautiful dinners and the charades she and her friends play, and the great performances they see at the end of the night, " Stuart said backstage.
Petrova will play Elena Dementieva in the last eight after her compatriot delivered a sure-footed performance to see off South African qualifier Chanelle Scheepers 6-1 6-3.
The play - opening at the Comedy Theatre in October - will see the 38-year-old play a former political prisoner who kidnaps a man she believes raped and tortured her.