Angelique Kerber bowed out of the Porsche Tennis Grand Prix, after going down to French tennis player Kristina Mladenovic 2-6, 5-7 here.
The Frenchwoman on Thursday broke the world No. 2 twice in the first set by taking advantage of poor serving by the German, who put just 45 percent of her first serves in play and failed to save either of the two break points she faced, reports Efe.
Kerber, who was the tournament's defending champion and had received a bye into the second round, was a bigger threat on return in the second set, but the 19th-ranked Mladenovic saved four of the five break points she faced.
The German top seed, meanwhile, drastically improved her first-serve percentage to 85 percent in the second set, but Mladenovic remained tough on return and earned two more service breaks, the last coming in the final game when she struck a forehand winner on match point.
"I'm so happy to be back on clay. It's my favourite surface," Mladenovic, a player who has had most of her success in doubles but has stepped up her singles game this year, said in an on-court interview after her victory.
She won her second career singles title earlier this year in St. Petersburg, Russia, and reached a career high ranking of No. 18 last month.
Kerber, for her part, is still without a title in 2017 after having a career year last year, when she won the Stuttgart event and both of the year's hard-court Grand Slam titles (the Australian Open and the US Open).