Wozniacki got off to a sluggish start. A four-time champion of the New Haven tournament, the fourth-seeded Wozniacki lost the first three games of the match against Bacsinszky, a qualifier. Wozniacki battled back to even the set at 4-4. But Bacsinszky got a break of serve in the next game, and then closed out the set by scoring on a drop shot.
"I have to give her credit, she started out well," Wozniacki said. "She got some matches under her belt playing qualifiers, and that helped her. I felt pretty good out there. It just took a while to get started."
There were several long rallies in the final two sets before Wozniacki prevailed. It was 2-2 in the third set before Wozniacki won the final four games.
"It took me a few games to get used to new balls and a faster court," Wozniacki said. "But I felt like I was getting stronger as the match went on. My confidence was high. I was in a great place mentally."
Earlier, seventh-seeded Sara Errani of Italy was eliminated by Garbine Muguruza of Spain 6-2, 3-6, 6-1. It was the third loss in the last four matches for Errani, who has been knocked out in the first round in two of her last three tournaments. Muguruza lost in straight sets to Errani at the 2012 U.S. Open in their only other meeting.
Samantha Stosur of Australia earned a 7-6 (8), 6-7 (10), 6-2 victory over Kurumi Nara of Japan. Stosur, who won the U.S. Open in 2011, blew three match points in the second set tiebreaker and let another match point get away before winning on her fifth chance. Stosur was given a wild card into the Connecticut Open.
Unseeded Carla Suarez-Navarro of Spain withdrew from the tournament because of a gastrointestinal illness. She was replaced by lucky loser Caroline Garcia of France, who beat qualifier Irina Carmelia Begu of Romania 7-6 (4), 7-6 (4).