Fifth-seeded Misaki Doi of Japan retired at the start of a third-set tiebreak, forfeiting to countrywoman and doubles partner Nao Hibino, 7-5, 5-7, 6-6 (ret.) on Monday in the first round of the WTA 250 event in Charleston, S.C.

Doi, who rallied from a 5-1 deficit in the second set by winning six straight games, could be seen playing through a cramp or pain of some sort. After serving to open the tiebreak and returning just one of Hibino’s shots, she walked over to the umpire’s chair to retire. The match featured eight converted break points by each player and lasted 3:09.

Eighth-seeded American Madison Brengle needed three sets to defeat Russian challenger Natalia Vikhlyantseva, 6-0, 3-6, 6-2. Vikhlyantseva broke Brengle’s serve twice to take control of the second set, but Brengle benefited from the Russian’s 11 double faults over the course of the match.

In a pair of matches pitting fellow Americans, third-seeded Shelby Rogers (NYSE:) cruised to a 6-1, 6-0 victory over Catherine McNally in just 1:02, and seventh-seeded Lauren Davis topped Coco Vandeweghe, 7-6 (3), 6-4.

Denmark’s Clara Tauson handled Liudmilla Samsonova of Russia, 6-3, 6-3, and sixth-seeded Australian Ajla Tomljanovic ended the day with a 6-1, 6-1 win over Mexico’s Renata Zarazua.

The event’s top two seeds, Ons Jabeur of Tunisia and Magda Linette of Poland, each will play their opening matches Tuesday.

–Field Level Media