Teenager Andreeva out of Stuttgart Open in last 16

Mirra Andreeva is ranked seventh in the world

Teenager rising star Mirra Andreeva went out of the Stuttgart Open as she lost in straight sets to fellow Russian Ekaterina Alexandrova in the last 16.

Sixth seed Andreeva, who has already won two titles this season, lost 6-3 6-2 against unseeded Alexandrova in just over an hour.

Andreeva, 17, became the youngest champion at a WTA 1,000 event in February by winning the Dubai Tennis Championships, before triumphing at Indian Wells in March.

But she was unable to wrestle control of Thursday's match from Alexandrova, 30, who claimed her fourth win over a top-10 player this season.

Alexandrova will play third seed Jessica Pegula in the quarter-finals after the American thrashed Poland's Magdalena Frech 6-1 6-1.

Italian fifth seed Jasmine Paolini beat unseeded German Jule Niemeier 6-1 7-5 to reach the last eight for the second successive year.

She will play American fourth seed Coco Gauff who cruised past Germany's Ella Seidel 6-1 6-1 inside 57 minutes.

Top seed Aryna Sabalenka will play Belgian Elise Mertens in the quarter-finals after Anastasia Potapova withdrew before their last-16 match with an injury.

The final last-eight tie sees Polish second seed Iga Swiatek take on unseeded Latvian Jelena Ostapenko, who holds an incredible 5-0 head-to-head record from their past meetings.

Ostapenko beat American seventh seed Emma Navarro 7-5 3-6 6-2.