Defending champion Madison Keys reaches 3rd round at the Australian Open

Defending champion Madison Keys survived a tough second-set challenge on Thursday but overcame fellow American Ashlyn Krueger 6-1, 7-5 to reach the third round of the Australian Open in Melbourne.

After sweeping through the first set, the ninth-seeded Keys fell behind 5-2 in the second set but rallied for the victory at John Cain Arena.

In another early match between two American women, sixth-seeded Jessica Pegula defeated McCartney Kessler 6-0, 6-2.

"I think I started really well and Ashlyn started a little bit slow," Keys said. "And then I was fully expecting her to raise her level, which she did. It just kind of got away from me a little quickly."

Keys said she tried to get back to basics, hoping she could at least prepare herself for a deciding third set.

Instead, she took the second.

"I just wanted to, even if I lost the (second) set, make sure I tried to get back in the set and try to figure out where my game kind of went and be able to get a few more points on the board," Keys said. "Once I kind of got back momentum I just tried to sink my teeth into the set and do whatever I could to get back into it."

In early men's matches, eighth-seeded Ben Shelton of the United States reached the third round, defeating Australian qualifier Dane Sweeny 6-3, 6-2, 6-2.

Two other seeded men also advanced. Fifth-seeded Lorenzo Musetti defeated fellow Italian Lorenzo Sonego 6-3, 6-3, 6-4, and No. 15 Karen Khachanov moved on with a win over Nishesh Basavereddy 6-1, 6-4, 6-3.

Later fourth-seeded and 10-time Australian Open champion Novak Djokovic was up against Francesco Maestrelli of Italy.