Edmund joins British greats with Dimitrov upset
Melbourne: The day of upsets saw unseeded Kyle Edmund make the semi-finals.
Nadal's 3-6 6-3 6-7 (5/7) 6-2 2-0 exit set up a last-four clash for the former US Open champion against Britain's Edmund, who stunned third seed Grigor Dimitrov 6-4 3-6 6-3 6-4.
There were no troubles for Edmund against Dimitrov, as he became only the fourth British man to reach the Australian Open semi-finals in the post-1968 Open Era.
"It's an amazing feeling. I'm very happy," said the overwhelmed 23-year-old, ranked 49.
"It was a hard match and I'm really trying to enjoy the moment. It was my first match on Rod Laver Arena and it's very special."
He is the only British man in the draw after Andy Murray's injury withdrawal before the tournament, raising the prospect that it will be him, rather than the Scot, who breaks through to win in Australia.
Murray has been a five-time finalist, but lost them all.
Romania's Halep plays her quarter-final against sixth seed Karolina Pliskova on Wednesday.
Wozniacki last made the semi-finals at Melbourne Park in 2011 and she faces a familiar foe lare Tuesday in Suarez Navarro, whose two wins in seven career meetings with her were both on clay.
"Obviously hard courts are a little different," said Wozniacki.
"But we've had a lot of tough encounters on hard courts as well. Three-set gruelling matches. I'm expecting a tough fight."