NEW YORK(AP) Top-ranked Dinara Safina overcame another shaky day of tennis Thursday to advance to the third round of the U.S. Open with a three-set victory over Kristina Barrois.

Safina won 6-7 (5), 6-2, 6-3, earning the victory despite 38 unforced errors and 15 double-faults in her second straight uncomfortably close match at Flushing Meadows.

She is ranked first despite having never won a major and she did little in this match against the 67th-ranked player in the world to cool the debate about whether she really belongs there.

No. 2 Serena Williams, going for her third major of the season, dispatched her opponent 6-1, 6-1 in 53 minutes in the final match Tuesday night in Arthur Ashe Stadium.

Safina, playing in the smaller Louis Armstrong Stadium for a Wednesday matinee, needed 2 hours, 13 minutes, much of which looked like the 2 hour-25 minute display she put on in the three-set opener against Olivia Rogowska.

In fact, the endings of the first sets were identical: Safina double-faulting on set point to lose a 7-5 tiebreaker. And, as in the first round, Safina came back with a stronger second set to win 6-2.

The third set was 3-3 when Barrois' game collapsed. She missed an easy forehand on break point against her in the seventh game, then committed five unforced errors over the final two games before losing it with a double-fault on match point.

Barrois finished with 43 unforced errors, including 17 in the final set.