Defending champion Keys survives mid-set wobble to advance

Defending champion Madison Keys has overcome struggles with her game to advance to the third round of the Australian Open with a 6-1 7-5 win over fellow American Ashlyn Krueger at Melbourne Park on Thursday.

The 30-year-old was once again less than convincing in her victory, two days after labouring in a first-round win over Ukrainian Grand Slam debutant Oleksandra Oliynykova.

Keys took 23 minutes to claim the opening set with a confident display that saw the American hit seven winners and convert all three break points against her compatriot in a one-sided start to the contest.

But the current world number nine allowed doubts to creep into her game in the second set, handing Krueger two breaks in serve with a succession of double faults that saw the 21-year-old open up a three-game lead.

Keys responded, however, by winning five games in a row to close out the match and progress to the next round.

"I started really well, and I think Ashlyn started a little slow, and then I was fully expecting her to raise her level, which she did," Keys said.

"Once I kind of got that momentum, I tried to sink my teeth into the set, and do whatever I could to get back into it."