Sara Errani struggled in the second set, but rallied for a straight-sets win Monday over Bethanie Mattek-Sands in the first round of the New Haven Open, the final hardcourt event before the US Open.

The fourth-seeded French Open finalist took the first set 6-4, then rallied from a 2-5 deficit to win five consecutive games to take the second 7-5.

Number seven seed Maria Kirilenko of Russia had an easier time, winning her first-round match 6-2 6-2 over Shahar Peer of Israel.

In other first-round action, Sweden’s Sofia Arvidsson defeated Melanie Oudin of the US 6-4 6-1, Mona Barthel of Germany downed Slovakia’s Daniela Hantuchova 6-3 7-5, fellow Slovakian Dominika Cibulkova accounted for Anabel Medina Garrigues of Spain 7-5 6-3, Andrea Petkovic of Germany beat Hungary’s Timea Babos 6-3 5-7 7-5, and Olga Govortsova of Belarus knocked out Russia’s Vera Dushevina 6-7 (5-7) 6-4 6-2.

Playing in only the third WTA main draw of her career, Nicole Gibbs also won, beating fellow qualifier Alexa Glatch 6-4 1-6 6-4.

Third-seeded Caroline Wozniacki, the four-time defending champion in New Haven, was scheduled to play her opening-round match later on Monday.