Maria Sakkari became the first Greek woman to qualify for the WTA Finals when the No. 3 seed cruised past Russia's Anna Kalinskaya 6-2, 1-0 (ret.) on Thursday in the second round of the VTB Kremlin Cup in Moscow.

Sakkari only needed half an hour to take the first set before Kalinskaya retired due to illness. The 26-year-old is currently ranked No. 7 in the world.

In the quarterfinals, Sakkari will meet former world No. 1 Simona Halep of Romania. The eighth seed defeated Russia's Veronika Kudermetova 6-1, 7-6 (4), prevailing after a tightly contested tiebreak.

No. 9 seed Anett Kontaveit of Estonia smashed five aces and took down German Andrea Petkovic 6-1, 6-4. She will face No. 2 seed Garbine Muguruza of Spain in the quarters. Also, Marketa Vondrousova of the Czech Republic defeated Lesia Tsurenko of Ukraine 6-3, 6-3 in their second-round matchup.

Tenerife Ladies Open

Romania's Irina-Camelia Begu completed a lengthy comeback and defeated Croatia's Donna Vekic 4-6, 6-2, 7-6 (4) in 2 hours, 49 minutes Thursday in the second round at Tenerife, Spain.

Begu, who had seven aces and converted seven break points, fell behind 3-1 in the third-set tiebreak before winning six of the final seven points.

China's Saisai Zheng won the other three-setter in the Canary Islands, a 7-6 (4), 2-6, 6-4 triumph over Danish No. 7 seed Clara Tauson. Zheng overcame Tauson in 2 hours, 48 minutes despite Tauson winning 53 percent of the games and fending off 10 of 16 break points.

Begu and Zheng advanced to the quarterfinals, as did No. 4 seed Camila Giorgi of Italy, Maria Camila Osorio Serrano of Colombia and Arantxa Rus of the Netherlands.