Iga Swiatek of Poland swept past Belgium's Elise Mertens 6-3, 6-4 on Thursday to reach the quarterfinals of the Porsche Tennis Grand Prix in Stuttgart, Germany.

Swiatek - the two-time defending champion who has never lost a match in Stuttgart - saved 5 of 7 break points while going 4-for-6 in breaking Mertens.

The four-time Grand Slam champion's next opponent will be 2021 US Open winner Emma Raducanu of Great Britain. Raducanu, who is on the comeback trail after wrist and ankle surgeries this time last year, beat Czech teenager Linda Noskova 6-0, 7-5.

Ukraine's Marta Kostyuk saved five match points in the 10th game of the third set while rallying to vanquish Chinese fifth seed Qinwen Zheng 6-2, 4-6, 7-5. Italy's Jasmine Paolini upset No. 7 seed Ons Jabeur of Tunisia 7-6 (8), 6-4, while No. 4 Elena Rybakina of Kazakhstan and No. 6 Marketa Vondrousova of the Czech Republic both advanced.

Open Capfinances Rouen Metropole

Arantxa Rus of the Netherlands toppled No. 1 seed Anastasia Pavlyuchenkova of Russia 6-3, 1-6, 6-3 in the Round of 16 in Rouen, France.

Rus won 7 of 13 break points, broke Pavlyuchenkova's serve seven times and capitalized on six double faults from her opponent.

Caroline Garcia of France had a much easier time than her seeded counterpart, beating Slovakia's Anna Karolina Schmiedlova 6-1, 6-0 in just 48 minutes. Anhelina Kalinina of Ukraine beat Italy's Martina Trevisan 6-2, 6-3.

Yue Yuan of China survived a two-hour, 47-minute encounter with France's Varvara Gracheva, prevailing 6-4, 4-6, 7-6 (6) after saving two straight match points in the third-set tiebreaker. Romanian Elena-Gabriela Ruse upset seed Clara Burel of France 6-0, 2-6, 6-3