Germany’s Kerber, champion two years ago, swept aside Madison Keys 6-1, 6-2, easily taming the American’s big serve and will go into her clash with the world number one on a 14-match win streak.
Top seed Halep was equally impressive on Rod Laver Arena in thumping sixth seed Karolina Pliskova 6-3, 6-2, reeling off nine games in a row after going 0-3 behind in the first set.
South Korea’s Chung battled past unheralded American Tennys Sandgren 6-4, 7-6 (7/5), 6-3 to become the lowest-ranked semi-finalist since Marat Safin in 2004.
Ranked 58, the bespectacled 21-year-old, nicknamed “The Professor”, proved too hot for his fellow quarter-final rookie, although he needed six match points before claiming victory.
“I’m just trying to stay focused, it’s my first time in one of these matches,” said the delighted Suwon native, who is the first player—man or woman—from his country to reach a Grand Slam semi-final.
Sandgren, who wiped his Twitter account ahead of the game after being dogged by controversy over his political views, paid tribute to the Korean.
“He’s a fantastic player,” he said, adding that he was also upbeat about his own future after a breakthrough tournament.
“I’m excited about that. Hopefully I can keep playing well.”
Next up for Chung, who has already knocked out six-time winner Novak Djokovic and fourth seed Alexander Zverev, is either defending champion Roger Federer or veteran Czech Tomas Berdych, who play an evening match.
Kerber, who won the title in 2016, is in scintillating form after an unbeaten singles campaign in the Hopman Cup and her triumph in the Sydney warm-up.
Keys was expected to be a stiff challenge, having not dropped a set en route to the quarters, but she melted under the German’s relentless groundstrokes and pinpoint return of serve.
“I’m just trying to find the feeling back I had like 2016,” said Kerber, who had a forgettable 2017 after winning not only in Australia but also the US Open in 2016.
“Madison is a hard hitter, and she served good. So I was trying to playing from the first point aggressive and moving good and also bringing a lot of balls back,” she added.
Stay calm
The win ensures Kerber, seeded 21, will move back into the world’s top 10.
Halep comes next on Thursday, with the nuggety Romanian taming towering Czech Pliskova’s serve to scamper into the last four for the first time in Melbourne.
“I didn’t have the best start, but I restarted after three games. I stopped missing so much and moved better,” said the Romanian, who showed no signs of the ankle injury that has been troubling her in previous rounds.
She is wary of Kerber and vowed to “stay calm and play like I did today”.
Swiss great Federer, zeroing in on a sixth Australian title and a 20th Grand Slam crown, holds a 19-6 lead over 19th seed Berdych dating back to their first meeting in 2004, and is also 4-0 over him in Melbourne.
But he is taking nothing for granted.
“I’m looking forward to play against him. He seems in good shape and I’m happy he’s over his back issues that he also had at the end of last year,” said Federer, who is 15 years older than his possible next opponent Chung.
