Christina McHale of the United States reached the third round at a fourth consecutive Grand Slam tournament.

Now comes the hard part: Trying to make it to the fourth round, something she's never done.

The 28th-seeded McHale, a 20-year-old from Englewood Cliffs, N.J., struggled a bit to close out her 7-5, 7-5 second-round victory over Mathilde Johansson of France on Thursday.

"It was weird: The first and second sets went exactly the same. I am still not finding my best tennis consistently over the two matches I have played," McHale said. "I was just staying in there, taking advantage when she does make some unforced errors and then just staying with it when she is playing really well. I still feel I can be a lot more offensive."

Next up for the American is a match against eighth-seeded Angelique Kerber of Germany.

"I'm going to have to return her lefty serve well, try and take advantage when I can, and not let her be dictating," McHale said.

The American got some compliments Thursday from 13-time Grand Slam champion Serena Williams, who was asked about McHale and called her "so tough; she has a great game."