Simona Halep had a markedly easier outing than in round three to reach the Australian Open quarter-finals, while Angelique Kerber won a compelling contest with Hsieh Su-wei.
World number one Halep has endured a gruelling tournament in Melbourne as she attempts to break her grand slam duck, but the Romanian needed just under one hour and 20 minutes to put Naomi Osaka to the sword in round four.
A resurgent Kerber has played her way into contention for a second Australian Open title, but had to negotiate her way past a tricky Hsieh on Rod Laver Arena.
HALEP MARCHES ON
The fact that Halep is still in the tournament is testament to her fortitude. In round one, she overcame an ankle injury and a 5-2 first-set deficit to defeat Destanee Aiava, before in the last 32 she survived three match points to win a deciding set 15-13 against Lauren Davis.
On this occasion, it was a more straight-forward 6-3 6-2 win over Osaka that punched her ticket into the last eight for the first time since 2015.
"I didn't expect to reach the quarter-finals. I didn't expect also to stop the tournament, even if I was injured. I had nothing clear in my head. I just went on court, [and] take it match by match," Halep said of her progress.
KERBER COMEBACK ENDS HSIEH CHALLENGE
Kerber has been resurgent this season and looks close to the form that saw her win the Australian and US Open in 2016, having toiled last year to slip down the rankings.
Hsieh has earned plenty of plaudits throughout the tournament, though, and proved a tricky customer for the German before succumbing to a 4-6 7-5 6-2 defeat.
Kerber, who outclassed Maria Sharapova in the previous round, said of her win: "I was everywhere today, inside and outside of the court, she made me run everywhere. She played a lot of shots into the corners, made a lot of drop shots, so I was trying to simply bring it back."
KEYS A CONTENDER, PLISKOVA DEFEATS CZECH RIVAL
Madison Keys was not widely talked up as a possible contender for glory in Melbourne, which is perhaps unfair given her run to the US Open final last year.
The American, who missed out on the tournament 12 months ago due to wrist surgery, put on a masterclass in a 6-3 6-2 win over Caroline Garcia, hitting 32 winners - including nine aces - en route to a 68-minute victory that booked a date with Kerber.
Karolina Pliskova also progressed to the last eight by overcoming Barbora Strycova 6-7 (5-7) 6-3 6-2.
It was the first time Pliskova had faced her Czech compatriot, since Strycova criticised her FedCup team-mate for employing her former coach Tomas Krupa.