Serena powers towards record title

A day after defending champion and top seed Angelique Kerber fell by the wayside, Williams overcame Barbora Strycova 7-5, 6-4 to set up a last-eight clash with Britain's Johanna Konta.

The American great would gain much from winning in Melbourne, as she would overtake Steffi Graf's Open-era record of 22 Grand Slam titles and end Kerber's short reign as world number one.

In hot conditions, she fought off the tenacious Strycova in two tight sets, following her sister Venus into the quarter-finals and staying on track for a possible all-Williams final.

"I have absolutely nothing to lose in this tournament," said Williams, 35. "Everything here is a bonus for me. Obviously I'm here to win. Hopefully I can play better, I can only go better."

Konta, the ninth seed, also reached the last eight with a perfect record in sets after a convincing 6-1, 6-4 victory over Russia's Ekaterina Makarova.

Despite the task facing her, Konta was delighted to be playing Williams, a childhood idol, for what would be her second straight Australian Open semi-final.

"I'm really looking forward to the challenge, and I'm looking forward to being on court, out on court with her and competing against her," Konta said.

'Tough little cookie'

Meanwhile Mirjana Lucic-Baroni wrote another chapter in her fairytale career revival when she beat American qualifier Jennifer Brady 6-4, 6-2 to reach her first Grand Slam quarter-final in 18 years.

The former teen prodigy, now 34, won the 1998 Australian Open women's doubles with Martina Hingis but she fled her abusive father and suffered a series of injuries to put her career on hold.

Her joy was unbridled at beating Brady as she reached the last eight at a major for the first time since 1999, when she lost to Graf at Wimbledon aged 17.

"I hope no one is going to pinch me and wake me up because this is just incredible," said Lucic-Baroni, who screeched with joy and jumped up and down to celebrate the win.

"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."

In the men's draw, David Goffin put away Austria's Dominic Thiem 5-7, 7-6 (7/4), 6-2, 6-2 to become the first Belgian man ever to reach the men's quarter-finals.

Goffin's win in the second-set tiebreaker proved crucial as he powered on to victory on Rod Laver Arena, where ambient temperatures were above 35 Celsius (95 Fahrenheit).

"I kept fighting, that was definitely key winning the second-set tiebreaker where I made some good returns," Goffin said.

"I continued to push on in the rallies and I'm really happy to win. Mentally, I'm tired."

In the quarter-finals, Goffin will play either Bulgaria's Grigor Dimitrov or Denis Istomin, the 117th-ranked Uzbek who upset six-time champion Novak Djokovic in round two.

Later, 14-time Grand Slam-winner Rafael Nadal, 30, takes on France's Gael Monfils and world number three Milos Raonic plays Roberto Bautista Agut of Spain.