Serena survives the smoke Down Under

Top seed Serena Williams toiled in searing heat and a smoke-filled atmosphere to reach the quarter-finals of the Australian Open today.

The American dropped serve twice in the first set before overpowering the 20-year-old Greek Eleni Daniilidou 6-4 6-1 as smoke from bushfires 200 kilometres to the north filled the skies.

Despite tournament officials evoking the Extreme Heat Policy to protect players' health, and with play suspended on the outside courts, Williams remained unworried by the heat.

"It's definitely very hot out here," she said. "But it could be worse. I live in Florida where when you walk out you lose 20 pounds because of the humidity and heat.

"I looked out my window this morning and didn't realise it was smoke," she said. "I thought it was foggy. It was a bit strange, but playing-wise I just blocked it. It wasn't a problem for me."

Williams, looking to win the only grand slam title to have eluded here, faces fellow American Meghann Shaughnessy in the last eight after Shaughnessy beat Elena Bovina in three tough sets, 5-7, 6-2, 6-4.

"That's great, it means that at least one American will be in the semi-finals," Williams smiled.

"I'm hoping it's me but as long as I have fun out here and am enjoying it, that's the main thing."

Eighth seed Anastasia Myskina reached the quarter-finals after fighting back to beat Chanda Rubin 4-6, 6-4, 6-1.

The 21-year-old Russian recovered from a poor start to level the match and then secured the key break in the second game of the deciding set with a fierce backhand down the line off a Rubin second serve.

Myskina gained the comfort of a double break in the fourth game thanks to another backhand pass as her 10th-seeded opponent's game fell to pieces.

The Russian completed the job on her second match point after an hour and a half to set up a clash with Kim Clijsters.

The fourth seed recorded a straight forward 6-3, 6-1 win over South African Amanda Coetzer.

The Belgian had 25 winners and clinched victory in just 57 minutes. She'll next meet eighth seed Anastasia Myskina of Russia, who had a 4-6, 6-4, 6-1 win over tenth seed Chanda Rubin.

Australian Open women's singles fourth round
4-Kim Clijsters (Belgium) beat 19-Amanda Coetzer (South Africa) 6-3, 6-1
8-Anastasia Myskina (Russia) beat 10-Chanda Rubin (US) 4-6, 6-4, 6-1
1-Serena Williams (US) beat 18-Eleni Daniilidou (Greece) 6-4, 6-1
25-Meghann Shaughnessy (US) beat 20-Elena Bovina (Russia) 5-7, 6-2, 6-4