Hobbled by back, ankle and knee injuries that forced her out of the tour for several months over the past two years, the 27-year-old German considered quitting tennis in 2013 to try her luck as a magazine journalist - and even successfully applied for internships.
But the player who enjoys writing blogs during her spare time could not switch off the lure of returning to the courts and her perseverance to regain full fitness paid off on Monday.
"One year ago... I was very close to quitting... just I didn't like playing anymore. I hated it," Petkovic, whose ranking plummeted to 177 last March, told reporters.
"When I came back from my injuries, my footwork was off, my strokes were bad. My serve was bad. I hated it. That's why I wanted to stop.
"(But) my life and destiny still wants me to play tennis ... and right now the only thing that I care about is tennis.
"I do have a lot of interests besides tennis, but nothing really gets my passion so far. I'm I think at the place where I need to be right now. And now I'm here and it's a nice reward."
Having missed the claycourt major for the past two years, 28th seed Petkovic spent Sunday "stalking" Bertens on YouTube for the whole day and that ploy enabled her to survive the fierce onslaught of the Dutchwoman's groundstrokes.
In a tournament that lost four of its top five women seeds before the start of the second week, Bertens initially looked set to become the lowest ranked female, at 148, to reach the last eight here since records started being kept in 1983.
The 22-year-old pulverised her opponent from the baseline in the opening set but Petkovic found a way to mute the thuds and after squandering a 4-2 lead in the third set, she broke for a 6-5 advantage and raised her arms in triumph after thumping away a forehand winner on match point.
A player who picked 19th century philosopher Friedrich Nietzsche "as the one who impressed me the most" - despite his "dark and sad" writings - will be hoping to pen a happier tale this week by reaching her first grand slam semi-final by beating either Jelena Jankovic or Sara Errani.
- Sports & Recreation