The defending champion Coco Vandeweghe was upset by Carina Witthoeft 6/7(3) 6/3 7/5 after two hours and 15 minutes. Vandeweghe didn't convert a match point on 5-4 in the third set, after that she had broken back her opponent.
The American got broken only twice, she hit 11 aces and six double faults, but it wasn't enough to beat Witthoeft. With this result Vandeweghe will lose at least 4 places and will be No. 29 by next week. Also the third seed Kiki Bertens was beaten.
The home favourite player lost to Andrea Petkovic 7/6(6) 2/6 6/2. It was a very close first set, where Bertens was up 4/2. She got broken back and in the tie-break Petkovic won converting her fourth set point. Kristina Mladenovic struggled in the first set against Risa Ozaki, beaten 7/5 6/1.
The French player, who is the defending finalist, will face in the second round Aliaksandra Sasnovich, who beat Anna Kalinskaya 6/3 6/4. The eigth seeded player Krystina Pliskova was beaten by Anett Kontaveit 6/7(5) 6/3 6/1 after an hour and 42 minutes.
Pliskova was very unconsistent, she hit 7 aces and 7 double faults, while Kontaveit played an aggressive tennis hitting 11 aces. After the close first set, the Estonian player dominated the match and saved all the two break points faced.
In the second round Kontaveit, who had beaten Kerber last month in Rome, will face Kirsten Flipkens who defeated Madison Brengle 6/1 6/2. It was a dominant match by Flipkens, who won in 48 minutes and won 80% first serve points.
Great win also for Evgeniya Rodina, who defeated the World No. 186 Miyu Kato 6/1 6/1 and will face Dominika Cibulkova or Antonia Lottner next. The home favourite player Richel Hogenkamp beat Mandy Minella 6/3 6/3, she will play against Korpatsch or Ana Konjuh on Thursday.
Andrea Hlavackova defeated the lucky loser Asia Muhammad 6/4 in the third set. Women's Singles Round 1 matches on Tuesday: