Serena sends Halep packing

A fired-up Serena Williams slugged past world number one Simona Halep Monday as she inches ever closer to a 24th Grand Slam title, while Novak Djokovic survived a battle to stay on course for a record seventh Australian Open crown.

In a towering performance, the American great scored her biggest win since having a baby to grind down the Romanian top seed 6-1, 4-6, 6-4 and move into a quarter-final against seventh seed Karolina Pliskova.

Czech Pliskova is another form player, winning the warm-up Brisbane International and easing past two-time Grand Slam winner Garbine Muguruza 6-3, 6-1 to set up the Williams clash.

"I'm such a fighter, I never give up," declared Williams after the epic encounter.

"It was an intense match and there were some incredible points but I love playing tennis and being out here and I love this court, it's really cool to be back."

While Williams stayed calm, highly-rated German fourth seed Alexander Zverev lost the plot against Canadian Milos Raonic, crashing 6-1, 6-1, 7-6 (7/5) and demolishing a racquet in a massive meltdown.

And Spain's Pablo Carreno Busta also let the pressure get to him, ranting at the umpire after a disputed call when leading the final tiebreak 8-5 against Japan's Kei Nishikori.

He failed to win another point and was booed as he stormed off Margaret Court Arena, angrily throwing his kit bag after losing a 5hr 5min marathon 6-7 (8/10), 4-6, 7-6 (7/4), 6-4, 7-6 (10/8).

Nishikori will now play six-time champion Djokovic, who dropped a set for the second match in a row before seeing off 15th-seeded Daniil Medvedev 6-4, 6-7 (5/7), 6-2, 6-3.

"It was definitely a physical battle. It was difficult to get through him," the Serbian world number one said. "In these kinds of matches you just have to hang in there."