"I have to say it was terrifying, but I did what what I had to do," said Peres, who conquered a long standing fear of heights in the process.
"In the ring I am in my element. Out there I wasn't. I was pretty scared actually. But I faced a really huge fear that I had and that for sure will help me in the ring - because I will fear no-one."
Hafner, who fights out of Ontario, Canada, is coming off an impressive victory over veteran American Carlette Ewell in North Carolina in June. Ewell, a former IBA light heavyweight champion who has also contested the WBC and IBO heavyweight titles, was comfortably out-pointed by Hafner over eight rounds.
That victory set up Hafner for a shot at Peres' WBO strap.
"The chance to be able to fight for a world title is something that doesn't come along every day," Hafner said. "The opportunity to be a part of women's boxing on the world stage is long overdue and I can't wait to bring that belt home to Canada."
"For too long women have been overlooked in the boxing ring. On October 4th we will once again show the world that we deserve our spot in this sport and put on one of the best fights the WBO has ever seen."
Perez, a naturalised Kiwi who hails originally from Brazil, captured her title with a thrilling 10-round points victory over fellow Kiwi Lani Daniels in March at a sold-out SKY CITY Convention Centre.
"That contest was rated by veteran ring announcer Lt Dan Hennessey as one of the finest he has ever witnessed – and Dan has seen some fights - but this fight could well top it," Steve Deane of promoter Rival Sports NZ said.
"Geovana is the type of boxer who never takes a backward step so with a big, tough international heavyweight coming her way it is sure to be an explosive contest.
"With Joseph Parker now fighting off-shore, this WBO world title fight is the biggest event on the Kiwi boxing calendar this year."
There is a lot on the line for Peres. A victory over a highly-rated international opponent would set up the possibility of a title defence on a major international card.
"We'll certainly be talking to our friends at Duco and Matchroom about the potential for Geovana to defend her world title on co-billing with Joseph Parker at some point," Deane said.
"But first she needs to beat Claire Hafner."
The October 4 date for Peres' title defence is two days before Kiwi UFC interim middleweight champion Israel Adesanya takes on Australian Robert Whittaker in a blockbuster trans-Tasman showdown for the undisputed UFC middleweight title.
"Kiwi combat sports fans are sure in for a heck of a weekend," Deane said.
The full undercard for Peres v Hafner and broadcast details will be confirmed in coming weeks.
