Mirjana Lucic-Baroni, who describes herself as "a tough little cookie," turned back the clock on Monday to reach the Australian Open last eight - her first Grand Slam quarterfinal in 18 years.

The unseeded Croat last advanced this far in a major at Wimbledon in 1999, when she lost to Steffi Graf, before personal problems and injuries derailed her career.

Lucic-Baroni earned another shot at cracking the final four after sweeping American qualifier Jennifer Brady 6-4, 6-2 in Melbourne, with Czech fifth seed Karolina Pliskova up next.

US Open finalist Pliskova reached the quarterfinals for the first time, beating Daria Gavrilova 6-3, 6-3 and ending Australia's involvement in the singles draws.

"It's pure joy. There's no other feeling than bliss," said Lucic-Baroni, who screeched with joy and jumped up and down to celebrate her win.

"I always said I have the game, but to work so hard and make so many sacrifices, I hope no one is going to pinch me and wake me up because this is just incredible.

"I am a tough little cookie and really stubborn. When I want something I will work hard and do anything I need to get it. What a satisfaction!"

The 34-year-old, who stunned third seed Agnieszka Radwanska in round two, made her debut at the US Open in 1997 at age 15 and teamed with Martina Hingis to win the 1998 Australian Open women's doubles.

In 1999, at 17, she went to the Wimbledon semifinals, but it all fell apart soon after as she was engulfed by heartbreaking personal issues.

In the background back then was tough, demanding father Marinko who, Lucic-Baroni later revealed, dished out regular beatings - which he described as "slaps" that were "best for the child".

Rough patch

Eventually Mirjana, her mother Andelka and four siblings fled Croatia in the dead of night for the sanctuary of the United States.

The drama, however, put the brakes on a journey that should have led to fame and fortune as financial problems put her career on the backburner.

Lucic-Baroni disappeared from top-level tennis for most of the 2003-10 period before slowly navigating her way back via lower-tier tournaments.

"I had a rough patch in my life early on, but I am really blessed with the family I have," she said.

Asked what advice she would give to young players facing hardships, she replied: "I'm going to get fined for saying this, but 'f' everything. If there's something you want to do, go and do it with all your heart.

"I'm not giving up. I've picked up a few more battle wounds but I'm pushing on," she added.

Lucic-Baroni was a prodigy when the Williams sisters began to make their mark in the 1990s.

The American siblings are also into the last eight at Melbourne Park, with the Croat on track to face Serena in the semifinals.

Despite the emotional roller coaster, Lucic-Baroni said she is not ready to call it a day just yet.

"I'm clicked in, for sure. I'm calm and focused now," she said. "The heart is a hundred percent, so that's all that matters."

Raonic rebounds into quarterfinals

Third seed Milos Raonic of Canada survived a potentially tricky match against Roberto Bautista Agut 7-6 (6), 3-6, 6-4, 6-1 on Monday to reach the Australian Open quarterfinals for the third straight year.

Raonic, who's been ill with the flu for the past few days, struggled at the outset against the 13th-seeded Spaniard.

The Canadian rallied from 5-1 down in the first-set tiebreaker to win the opening set, then was broken twice in the second set.

But Bautista Agut began to falter midway through the third set when the roof at Hisense Arena was closed due to a passing rain shower, and he later had to call for a trainer to work on his leg.

"I was very fortunate to get through today," Raonic said. "There were moments where it wasn't looking so good."

Raonic, 26, fired down 33 aces and 75 winners, but also 55 unforced errors, including nine double faults in the two hour, 52 minute contest as he continues his quest for a first Grand Slam title.

Raonic is seeded third for the first time at a Grand Slam, and the top two seeds, Andy Murray and Novak Djokovic, are already out of the event.

Mirjana Lucic-Baroni of Croatia celebrates her fourth-round victory over American Jennifer Brady at the Australian Open in Melbourne on Monday. The 34-year-old former child prodigy reached her first Grand Slam quarterfinal in 18 years. Aaron Favila / Ap