No.5 seeds Lyudmyla Kichenok of Ukraine and Jelena Ostapenko of Latvia pulled off a comeback from a set and a break down on Saturday to advance to the semifinals of the WTA Finals. 

Kichenok and Ostapenko took just over 2 hours to squeak past No.7 seeds Anna Danilina of Kazakhstan and Beatriz Haddad Maia of Brazil 6-7(7), 6-4, [10-8] in round-robin play in the Pam Shriver Group.

Kichenok and Ostapenko's ticket to the semifinals was confirmed after group winners Veronika Kudermetova and Elise Mertens defeated Gabriela Dabrowski and Giuliana Olmos 7-6(5), 6-2. Kudermetova and Mertens finished round-robin play undefeated. 

Kichenok and Ostapenko are now 2-0 against Danilina and Haddad Maia, having also beaten them en route to the Cincinnati title earlier this year. 

There were no service breaks in the first set, although Danilina and Haddad Maia had to save a set point at 5-4, and another at 7-6 in the tiebreak. Danilina and Haddad Maia converted their third set point with a volley winner by the Brazilian.

However, Kichenok and Ostapenko reeled off five straight games from 2-0 down in the second set to take control. Ostapenko served out the set at 5-4, forcing a long Haddad Maia return on deciding point to seal it.

Very little separated the teams in the decisive match-tiebreak, but Kichenok slammed a volley winner to line up two match points at 9-7. Kichenok missed her return on the first, but she forced an error with another strong volley to wrap up the win on the second.