No. 1 seed 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 U.S. 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.