No.4 seed and defending champion Ons Jabeur was knocked out of the bett1open in Berlin on Tuesday by German qualifier Jule Niemeier, 7-6(4), 6-4.

The win is Niemeier's third career Top 10 victory, and second on grass. En route to the quarterfinals at Wimbledon last summer, she beat then-No.2 Anett Kontaveit. It was also Niemeier's first WTA main-draw victory since her second career Top 10 win, which came over Petra Kvitova in the first round of the Mutua Madrid Open in May. 

Stat of the day: Niemeier was 0-2 in the main draw in Berlin in the last two years, losing three-setters to Belinda Bencic in the Round of 32 both times.

This year, she won two three-setters in qualifying to reach the main draw, and needed those fighting qualities against Jabeur in a first set that lasted nearly an hour. 

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"It's an amazing feeling, to be honest," Niemeier said. "I lost in three sets the last two years, so when I won the first set, I was like, 'At least I can play three sets again like the last two years. I was pretty positive, and it feels amazing to get the win today." 

How the match was won: Ranked No.120, Niemeier scored the upset in 1 hour and 35 minutes, even though Jabeur hit more aces (7 to 1) and more winners (19 to 12). But the German was more efficient on break point opportunities (3-for-3) than Jabeur, who only converted two of the six she created, and also won 12 of 16 points coming forward to net. 

Neimeier saved two set points on serve in the ninth game of the opening set, a set in which she trailed 5-3. She also won the last four points of the tiebreak. In set two, Niemeier broke serve in the opening game and held onto the lead for the duration of the match; after missing her first match point, she denied Jabeur a chance to level at 5-5 with some dogged defense -- the Tunisian missed a forehand in the net when she tried to change direction down the line -- before finishing off the victory when Jabeur's final forehand went long. 

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"It was tough. I felt my nerves. I [was trying] to break her at 5-3, but I didn't," Niemeier said, "so I kept trying to stay positive, play point by point. In the end, I was a bit nervous, but I'm really happy that she missed in the end." 

Up next: Neimeier will next face either 2019 US Open champion Bianca Andreescu, or 2019 Roland Garros runner-up Marketa Vondrousova. Due to rain that delayed play early in the day, that match was pushed to Wednesday.