Top seed Caroline Wozniacki made a winning start to the Qatar Airways Tournament of Champions in Sofia on Tuesday.
The round-robin tournament marks the end of the WTA International Series and brings together the six highest-ranked winners of events in the series along with two wild cards.
The Dane broke serve twice in the first set and three times more in the second as she cruised past Hsieh Su-wei of Chinese Taipei 6-2 6-2 in just an hour.
In the other match in the same group, Italy's Roberta Vinci was an equally comfortable 6-1 6-2 winner against Daniela Hantuchova.
Bulgarian wild card Tsvetana Pironkova justified her inclusion with an opening win over Jie Zheng in the other group.
Jie took the first set, but Pironkova battled back to win 2-6 6-4 7-6 (7/4) in more than two hours and 40 minutes.
