One by one, Serena Williams' French Open challengers fell at the Porsche Tennis Grand Prix, until the only one left standing was Germany's Angelique Kerber.

SI.com reported that Kerber, the No. 14 player in the world, knocked off No. 5 Caroline Wozniacki 3-6, 6-1, 7-5 to capture event in Stuttgart. With the French Open now less than a month away, Kerber, who is now on an 11-match winning streak, rallied from a 3-5 deficit in the third set to knock off Wozniacki.

Caroline Wozniacki beats Simona Halep for breakthrough win on clay

Kerber also knocked off No. 2 Maria Sharapova, a three-time defending champion at the event, on her way to the title. Wozniacki took care of No. 3 Simona Halep and seemingly was on her way to her biggest title in years.

According to SI.com, it was Kerber, who became the aggressor when the match was on the line.

"Wozniacki's disappointment from coming so close only to fall short was obvious and understandable after the match," SI.com reported. "She had the trophy on her racket, serving at 5-4, 30-all in the third set. But as she built her lead in the third set and the trophy was so tantalizingly close, Wozniacki forgot what got her there. She began to revert to a more defensive style and it was Kerber who stepped up and went for her shots. Even when she was down in the scoreline, Kerber was looking to dictate, while Wozniacki fell into her reactionary patterns, running everything down and hoping Kerber would miss.

"The question surrounding the Dane's game has always been whether she can transition into a more aggressive player, one who steps in and looks to dictate with her shots. Her legs may win her matches, but alone they will not win her titles. The more aggressive player wins out in the big matches."

There still are a couple of events before the French Open begins on May 25, but Kerber has the most momentum riding into May.

Williams has a 5-1 record, including the last four straight, against Kerber. Kerber last beat Serena at the Cincinnati Masters in 2012, and all their matches have been on hard courts. That may seem to be one-sided but none of the top players have any better record against the world's No. 1.