Jessica Pegula finished round-robin singles play at the WTA Finals with a 3-0 record a year after going 0-3 at the season-ending championship, heading to the semifinals with a 6-3, 6-2 victory over Maria Sakkari.
The fifth-seeded Pegula extended her overall winning streak to eight matches, including a title at the Korean Open last month.
The 29-year-old American has won all six sets she's played in Cancun so far and will play in the semifinals on Saturday. Sakkari, who is ranked No. 9 but got into the eight-player field when No. 8 Karolina Muchova withdrew with an injured right wrist, went 0-3 and dropped every set.
Pegula had fewer winners than Sakkari, 12-7, but also made roughly half as many unforced errors, 35-18, on a windy evening with some brief rain.
The other semifinalist from their group was to be determined later Thursday, when No. 1-ranked Aryna Sabalenka was scheduled to face Elena Rybakina in a rematch of this year's Australian Open final. Sabalenka won that matchup in January for her first Grand Slam title.
Pegula already had clinched first place in the four-player group by virtue of earlier straight-set victories against Sabalenka and Rybakina on the outdoor hard court built for the event.
The two semifinalists from the other singles group will be settled Friday, when U.S. Open champion Coco Gauff takes on Wimbledon champion Marketa Vondrousova, and four-time major champ Iga Swiatek meets three-time Slam runner-up Ons Jabeur.
