Caroline Wozniacki remains undefeated at the New Haven Open.
The four-time defending champion beat Ekaterina Makarova 6-3, 6-3 in the first round Monday, her 18th consecutive victory at the tournament.
She first entered the event in 2008 when it was known as the Pilot Pen.
"Everything about the tournament and around the tournament just makes me feel at home and makes me feel like I can play well here," she said.
Wozniacki was broken in the opening game, but won the next five to take control of the first set.
Makarova got another early break in the second to go up 2-0, but Wozniacki rallied again, getting a break to tie the set 2-2, another in the seventh game to take the lead and a third to close the match.
The 22-year-old Dane had to play in the first round for the first time since 2009, after being seeded third behind Agnieszka Radwanska and Petra Kvitova.
"I think the last few years I've had a bit of an easier opponent in the first round — I've played 'Bye," she said. "I'm pretty comfortable playing 'Bye.' This year, unfortunately, 'Bye' wasn't there."
She will face Sofia Arvidsson of Sweden in the second round. Arvidsson beat Melanie Oudin 6-4, 6-1.
Sara Errani of Italy struggled in her second set, but rallied for a 6-4, 7-5 win over Bethanie Mattek-Sands. The French Open finalist and fourth seed won her first set 6-4, then rallied from a 2-5 deficit to win five consecutive games.
Mattek-Sands, still looking for her first WTA career win after 13 seasons, is ranked 216th in the world. Errani is ranked 10th and already has won four titles this season.
Maria Kirilenko of Russia had an easier time, winning her first-round match 6-2, 6-2 over Shahar Peer of Israel.
It was a good day for Kirilenko, who also received a car from the Russian government as a reward for taking home the Olympic bronze medal in London. Her mother picked up the Audi on Monday.
"It's difficult to start the first matches on hard court," she said. "It's different movement and different bounce and different balls, completely different than on grass courts at the Olympic Games and Wimbledon."
Kirilenko advanced to a second-round match with Germany's Mona Barthel, who eliminated Slovakia's Daniela Hantuchova 6-3, 7-5. It was Hantuchova's earliest departure in her 10 tournament appearances in New Haven since 2001.
Playing in only the third WTA main draw of her career, reigning NCAA champion Nicole Gibbs also won, beating fellow qualifier Alexa Glatch 6-4, 1-6, 6-4.
Gibbs will face Kvitova, the 2011 Wimbledon champion, in the second round. The 22-year-old Kvitova is having a good hard-court season, following up a win at the Rogers Cup with a run to the semifinals in Cincinnati last week.
She asked for a wild-card entry at New Haven and ended up with the second seed and a first-round bye. She said all these matches should help her be ready for next week's U.S. Open.
"You know you can practice forever," she said. "But the matches are the important practice for the tournament."