Volkswacht Bodensee - Keys blows hot and cold before making Australian Open third round

Keys, who upset Aryna Sabalenka in last year's final, admitted after her laboured first-round win that she was a bundle of nerves and "too timid".

The 29-year-old threw off the shackles in the first set against the 92nd-ranked Krueger, taking it in just 23 minutes on John Cain Arena before losing focus and having to rally from 2-5 down in the second.

"I started really well and Ash a little slowly," said Keys, who began her season with quarter-final exits at Brisbane and Adelaide.

"I fully expected her to raise her level and she did. It got away from me a bit."

After taking more than an hour to win the first set in the opening round, Keys rushed through it this time on a cool Melbourne Park morning, breaking on three occasions.

Hitting well and pushing Krueger around the court, the ninth seed looked ominous and held to love in opening her second set account.

But Krueger, consulting a book at the changeovers, upped her intensity and against the odds broke Keys to lead 3-2 after the American's serve imploded, double-faulting three times.

Keys was broken again, to love and once more on a double-fault, to slump 5-2 behind as she lost focus.

However, she gathered herself to break back then held before a double-fault on break point from Krueger in the next game put her back in the hunt and the title-holder made no mistake in sealing the win.

She will meet either Karolina Pliskova of the Czech Republic or Indonesian prospect Janice Tjen next.

M.Vogt--VB