NEW YORK—Bethanie Mattek-Sands, who will play Serena Williams in the third round of the U.S. Open, says she will attack the world No. 1 whenever she can.

“She’s playing great. Right now she's on a mission to get a record, and I’m here playing my game,” Mattek-Sands said. “I think it’s going to be a battle out there. I'm going to do my best. Obviously Serena's pretty aggressive. She’s going to rip some balls, hit some big serves. I think it’s going to be a good match. That’s obviously going to be the clash there. I’m excited for it.”

Mattek-Sands, 30, and Williams, 33, know each other well, but the Americans have only played each other twice, with Williams winning their meetings in 2006 and 2008.

Mattek-Sands beat CoCo Vandeweghe convincingly in the second round, 6-2, 6-1. The veteran has been injured a number of times during the past six years, and says that if she had been completely healthy through her career, she might have retired already.

“It's like I’ve been saving all my matches and tournaments for the back end of my career,” said Mattek-Sands, who has won 17 doubles titles and reached four singles finals. “I have missed a lot of tournaments. I think I only averaged like eight to nine tournaments a year just with my injuries. I think players retire because either they mentally don’t want to do it anymore or physically stop doing it. Right now mentally I’m right there and physically I’m feeling great, so I’m happy to keep playing.”