Petkovic's run to the final here in 2010, which included wins over Petra Kvitova and Ana Ivanovic, is her best grass court result to date. Wickmayer has proven several times that she is dangerous on grass, most notably with runner-up showings at Birmingham in 2008 and here in 2009.
Petkovic, who lost her one previous match-up with Wickmayer in straight sets in Doha earlier this year, was coming off a semifinal showing at Roland Garros - the best Grand Slam outing of her career. The fifth-seeded Petkovic continued her strong form on Sunday with a 6-2, 6-4 triumph.
"I was very satisfied about the way I played, especially for my first match of the season on grass," Petkovic said. "I was very nervous before because I had lost to her previously, and her game is well-suited to grass. But I served well most of the time and I moved well. There are a few things I need to improve for the next match, but all in all, I'm quite satisfied."
Next up for Petkovic is Magdalena Rybarikova, against whom she has lost both of her previous encounters - one coming in the 2013 Washington final and the other in the first round of this year's Australian Open.
Rybarikova was a 6-4, 6-4 victor over An-Sophie Mestach, never facing a break point and securing both of her breaks in the first game of each set.
Securing main draw berths with qualifying wins were Mona Barthel, CoCo Vandeweghe, Julia Glushko and Olga Govortsova, who will square off with World No.3 and defending champion Simona Halep in the first round of the main draw.
First round doubles winners included No.3 seeds Michaella Krajicek and Kristina Mladenovic and No.4 seeds Marina Erakovic and Arantxa Parra Santonja. Krajicek and Erakovic won this title in 2008 alongside each other. Parra Santonja was runner-up here last year with Dominika Cibulkova.