(Photo credit: Mike Frey-Imagn Images)

Seventh-seeded Karolina Muchova of the Czech Republic and Russian eighth seed Ekaterina Alexandrova both advanced in routine fashion to the Round of 16 on Tuesday at the Porsche Tennis Grand Prix in Stuttgart, Germany.

Muchova cruised past qualifier Aliaksandra Sasnovic of Russia, 6-2, 6-4, while Alexandrova dispatched of Gabriela Knutson of the Czech Republic, 6-2, 6-2 on the clay of the WTA 500 event.

Those two were the only seeded players in action on the second day of competition. In other matches, Belgium's Elise Mertens won a 6-3, 6-4 decision over Germany's Ella Seidel; Canada's Leylah Fernandez broke Alexandra Eala of the Philippines four times en route to a 6-1, 6-4 triumph; Germany's Eva Lys edged Spain's Paula Badosa, 2-6, 7-5, 6-4; and Russia's Diana Shnaider overwhelmed German wild-card entry Tamara Korpatsch, 6-3, 6-1.

Shnaider will face top-seeded Elena Rybakina of Kazakhstan on Thursday in the round of 16.

Rouen Metropolitan Open

Top-seeded Marta Kostyuk of Ukraine needed only 77 minutes to defeat France's Diane Parry 6-1, 6-4 to advance to the Round of 16 in Rouen, France. Kostyuk capitalized on 5 of 6 break points and won 24 of 41 points (53.7%) on Parry's service.

The three other seeded players in action on the clay also advanced, but needed three sets to get to the finish line. No. 3 Jaqueline Cristian of Romania needed nearly three hours to subdue France's Tiantosa Rajaonah, 2-6, 7-6 (6), 7-5 and No. 4 Hailey Baptiste rallied past France's Jessika Ponchet, 3-6, 7-6 (6), 6-2. Seventh-seeded Elisabetta Cocciaretto of Italy survived a three-set challenge from Russia's Alina Charaeva, 6-3, 4-6, 6-2.

In other matches, Dominika Salkova of the Czech Republic bested Russia's Anna Blinkova, 7-5, 6-1; Russia's Iryna Shymanovich defeated the Czech Republic's Linda Fruhvirtova, 6-3, 7-5; Caty McNally rallied past Katie Volynets, 1-6, 6-1, 6-1 in an All-American showdown; and China's Xinyu Wang edged France's Chloe Paquet, 3-6, 6-4, 6-4, in a battle of qualifiers.

--Field Level Media