Lindsay Davenport inspirational for Madison Keys

Melbourne: Madison Keys has been touted as a talented prospect for several years and came of age in beating Australian Open fourth seed Petra Kvitova, with former great Lindsay Davenport behind her transformation.

The unseeded American, 19, made her Grand Slam debut at the US Open in 2011 as a 16-year-old and has been steadily climbing the rankings since.

But her 6-4, 7-5 win over reigning Wimbledon champion Kvitova, setting up an all-American last 16 clash with Madison Brengle, was her biggest scalp yet.

She enlisted the help three-time major winner Davenport in the off-season and judging by her composed showing on Rod Laver Arena in a prime-time Saturday evening match the partnership is already flourishing.

"Lindsay and (husband) Jon have been amazing -- it was a great off season, I learned a lot and I`m just really happy that they`re here supporting me," world number 35 Keys said, with Davenport in the crowd overseeing her charge.

Like Davenport, Keys is a big-serving baseliner with powerful groundstrokes, which she used to full effect against Kvitova, who admitted to struggling with nerves throughout the tournament.

It is not often the world number four plays second fiddle in the power department, but Keys constantly forced onto the back foot and it slowly took its toll with Kvitova producing an error-strewn game.

"She was just telling me she has a great serve, so try to make her play as many balls as possible," Keys said of Davenport`s advice.

Keys, who has never before advanced beyond the third round of a major, now faces Brengle, herself in a Grand Slam fourth round for the first time.

Sharing the same name and from the same country, the pair are friends.

"I mean, Maddie is a great player. She has been around for a long time," she said of Brengle, who made her Grand Slam debut in 2007 then dropped off the radar for several years, playing on second string circuits.

"She`s always that person that can squeak out wins. She makes a million balls and she fights. So I think it`s exciting. 

"I think it`s pretty cool that there`s not only two Americans playing each other in the fourth round, but that we have the same name," she added.

Following her breakthrough win Keys admitted she was shaking and her mind was racing.

The level-headed Davenport, who won the title at Melbourne Park in 2000, will ensure her focus is back on the job in time for her next outing on Monday, although she had others things on her mind immediately after the match.

"After the match she was telling me she got pooped on by a bird. I saw a video of it. That was pretty much all we talked about after the match so far," said the ecstatic teenager.