CARLSBAD, Calif. (AP) -- Third-seeded Agnieszka Radwanska of Poland was extended before winning her opening match with a 6-0, 7-6 (4) victory over Great Britain's Elena Baltacha in the Mercury Insurance Open on Tuesday.
Radwanska, who received a bye into the second round, saved two set points at 5-4 in the second set before Baltacha saved one match point to force the tiebreaker.
No. 3 ranked and top-seeded Vera Zvonareva of Russia plays her first match at night against U.S. qualifier Jill Craybas, followed by second-seeded Andrea Petkovic, who opens with American Alexa Glatch.
Two seeded players lost as qualifier Marina Erakovic of New Zealand upset No. 14 seed Elena Vesnina of Russia 6-1, 6-2 and Alberta Brianti of Italy was a 1-6, 6-2, 6-2 winner over 10th-seeded Flavia Pennetta of Italy.