Denmark's former world number one Wozniacki, now ranked 11th, needed barely over an hour to see off the Taiwanese fifth seed, relying on a consistent service game and her battling abilities to save two of the three break points she faced in their first Group Serdika clash.
Wozniacki, who won titles in Seoul and Moscow to qualify for the event in Bulgaria, made no double faults and landed 76 per cent of her first serves to dominate the match, winning all five of her break points and taking all-but 16 of her service points.
"I always try to finish my matches in two sets and I am happy that this time it worked," said Wozniacki. "I will try to finish this season with a hat-trick."
Roberta Vinci won the opening match in that group 6-1 6-2 over Daniela Hantuchova.
The Italian world number 16, seeded fourth in the equivalent to a second-tier version of the WTA Championships, needed only an hour and five minutes to see off the Slovakian seventh seed in their round-robin clash.
The event features eight players in two round-robin groups, featuring the highest- ranked players who won titles this season, excluding those involved in the main WTA Championships, plus local wildcard Tsvetana Pironikova, who surprised Zheng Jie of China 2-6 6-4 7-6(4) in Group Sredets.
Group Sredets is headed by world number 13 Nadia Petrova of Russia, who starts her campaign against Jie on Wednesday.
1-Caroline Wozniacki (Denmark) beat 5-Hsieh Su-Wei (Taiwan) 6-2 6-2
4-Roberta Vinci (Italy) beat Daniela Hantuchova (Slovakia) 6-1 6-2
8-Tsvetana Pironkova (Bulgaria) beat 6-Zheng Jie (China) 2-6 6-4 7-6(4)