NEW YORK (AP)— Serena Williams says her back is feeling better with rest.

The 15-time Grand Slam champion turned her right ankle in her first-round match at the Australian Open, then hurt her lower back in her quarterfinal loss to fellow American Sloane Stephens because she says she was compensating for the ankle.

Williams pulled out of the Dubai Championships on Feb. 20, citing the back injury. Her next tournament is in Miami in two weeks, but first she's got an exhibition match against Victoria Azarenka on Monday night at Madison Square Garden. Rafael Nadal also faces Juan Martin del Potro in the event.

Last month, the 31-year-old Williams became the oldest woman to reach No. 1 in the rankings.