The 2016 champion routed Maria Sharapova 6-1, 6-3 in a third-round win that showcased her credentials as a title contender and ensured she'll be the only Grand Slam champion still playing in the second week in the women's draw.
Second-seeded Federer's next opponent is former world junior No. 1 Marton Fucsovics, who beat Nicolas Kicker in straight sets. As well, it was Federer's 90th match win at Melbourne Park.
And Halep, already nursing an ankle injury after her first-round victory against Australian qualifier Destanee Aiava, was keen to bypass tennis talk.
She saved one match point in the ninth game on her serve before Hsieh served out the match in the next, clinching it with a winning backhand to the corner.
"Of course is quite a big match".
"For sure. A ton of positives", she said of what she took from the fight. "I felt something and I couldn't really put any pressure - it was my right toe", she added.
"I learned a lot from the last 12, 24 months". "I was a little bit frustrated because of the leg". "I never played the third set so long".
Sharapova said Kerber was the more aggressive on court and took more risks.
"There's a lot of Voltaren and painkillers in her system".
In the second set, Sharapova was broken while serving for the match, sending it to the tiebreaker which she dominated.
Afghans to play maiden Test in June
Afghanistan will make play their inaugural Test match between June 14 and 18 when they take on India in Bangalore. The first five-day game under lights was played between Australia and New Zealand in 2015.
News of Note-AT&T and Huawei, Sprint and SoftBank and more
Neither of the companies offered official statements, but AT&T did tell Reuters that it's yet to make a decision on 5G suppliers. AT&T has also been warned to avoid using Huawei hardware for their subsidiaries like Cricket Wireless.
Girl should be allowed to take medical marijuana at school: suit
Jim and Maureen Surin have sued the state of IL on behalf of their daughter Ashley (right) over the state's medical marijuana law. An 11-year-old girl who is suffering from leukemia can now use medicinal marijuana at her elementary school.
She served for the match at 8-7 ahead in the decider but was unable to earn the victory, and she then had to recover from 0-40 down with world No. 76 Davis 11-10 ahead.
Courageous unseeded American Lauren Davis lost a middle toenail on her left foot and had to be treated twice by the physio as she threw everything at Halep in a third set that alone lasted 2hr 22min.
"After this match I think tomorrow (the ankle) is going to be worse, but I just push, push myself, and we will see what's going to happen", said Halep, a quarter-finalist at Melbourne Park in 2014 and 2015.
And No 8 seed Caroline Garcia emerged as the victor of the second match in the Margaret Court Arena while the first in the Rod Laver Arena continued, the Frenchwoman beating Aliaksandra Sasnovich 6-3 5-7 6-2.
A much-hyped match between two former Australian champions was no contest: 2016 victor Angelique Kerber beat Maria Sharapova 6-1, 6-3 on Rod Laver Arena to open the night program.
Six-time champion Novak Djokovic is through to the Australian Open's fourth round after a 6-2, 6-3, 6-3 win over Albert Ramos-Vinolas. It was not easy, but I just kept playing.
Keys missed last year's Australian Open after undergoing surgery to fix her injured left wrist. The 17th-seeded Kyrgios won the last five points after falling behind 5-2 in the tiebreaker.
"It definitely was a very tough match".
Tomas Berdych ended the Australian Open campaign of Juan Martin del Potro, beating the Argentinian 6-3, 6-3, 6-2. He next meets Hyeon Chung, who ousted new generation star, Zverev.
Another unexpected loss at a major had the highly-touted Zverev admitted he may have a problem. He's won five tour-level titles, but never gone beyond the fourth round at a major.