On a day when top seed Sloane Stephens survived a scare before beating Ajla Tomljanovic 4-6, 6-4, 6-4, Sakkari showcased supreme court coverage skills throughout her almost two-hour match against Bertens.
Williams had little trouble against the 31-year-old German although the gusty breezes at Auckland Tennis Centre played havoc with her ball toss, especially when she was serving for the match at 5-3 in the second set.
Former world number one Garbine Muguruza was beaten 7-5, 6-4 by Aryna Sabalenka in the China Open second round on Tuesday while an ailing Jelena Ostapenko lost 6-0, 6-0 to Wang Qiang.
Roger Federer gained a measure of revenge against Wimbledon nemesis Kevin Anderson, beating the South African 6-0, 6-4 at the Miami Open on Thursday to set up a mouthwatering semi-final against a player barely half his age.
Perry said she had been in touch with the local organising team on a daily basis as they prepare to start the tournament on October 19, pending government approval and confirmation that players will be able to travel.
Halep became the first Romanian to reach the summit of the women's rankings when she beat French Open champion Jelena Ostapenko in the semi-finals of the China Open in Beijing, a feat she feels is the high point of her career to date.
Spain's Carla Suarez Navarro came back from a dreadful first set to defeat Venus Williams.
Here are some of the best moments from the 2019 Australian Open.
Petra Kvitova takes on Naomi Osaka in Saturday's Australian Open final with one of them set to emerge as a fresh champion at Melbourne Park as well as the new world number one.
Reaching top of the world seemed to agree with Angelique Kerber, who celebrated her ascension to world number one with a 6-4, 6-3 win over Caroline Wozniacki on Thursday to advance to the US Open final.
Serena Williams will be wary of another semi-final slip-up when she takes to the Arthur Ashe Stadium court on Thursday to face 10th seed Karolina Pliskova for a spot in the US Open final.
The Romanian broke Williams's serve in the first game but that was the only one she managed for the rest of the opening set as the American bulldozed her way through the set in 20 minutes, serving it out with an ace.
The 23-year-old Wimbledon champion, who climbed to the top of the WTA rankings on Monday, hardly broke sweat against the Frenchwoman, ranked 20th in the world, on her way to victory in an hour and 20 minutes.
Top-seeded Serena Williams said on Friday that she was not sure about the state of her balky right shoulder but felt more relaxed entering next week's US Open than last year.
The 33-year-old Swiss, ranked 261 in the world after two knee surgeries, served solidly throughout a one-sided contest on the slick centre court, easing past an opponent who struggled to cope with Wawrinka's power.
Britain's Johanna Konta has learned much from matches against Grand Slam champions and former world number ones over the last 18 months but on Wednesday her education will be complete when she faces Serena Williams in the Australian Open quarter-finals.
Mirjana Lucic-Baroni could barely contain her joy after continuing her remarkable run at the Australian Open to reach her first grand slam quarter-final since the 1999 Wimbledon championships on Monday.
The World No 2 announced her commitment to the social media entrepreneur shortly before the New Year and while it was "great", she was pushing it to the back of her mind, at least until after Melbourne Park.
Maria Sharapova's claycourt season got off to a poor start on Tuesday as she lost in three sets to Caroline Garcia in the first round of the Porsche Tennis Grand Prix in Stuttgart.
'Maybe the last tournament changed something in people's minds but not in mine. I'm really enjoying every match but, still, I think I do have lot of things to improve'
The 20-year-old, looking to become the first unseeded woman to lift the Suzanne Lenglen Cup since 1933, blazed her way to the final, hitting winners and errors with reckless abandon.
Romanian Simona Halep showed the full extent of her defensive skills to beat Karolina Pliskova 6-4, 3-6, 6-3 and reach her second French Open final in Paris.
At one stage Yuki was a break up, serving for the opening set but lost his serve and eventually the set. After drawing parity, Yuki twice lost his serve to fall behind 0-3 in the decisive set and never recovered.
The latest tennis rankings have been announced by the ATP and WTA
Novak Djokovic wore down Lucas Pouille after an even first set, dispatching the Frenchman 7-6(2), 6-1 in a Cincinnati Masters quarter-final in Ohio on Friday.
Former World No 1 Ana Ivanovic was upset 7-5, 6-4 by 42nd-ranked Karolina Pliskova of the Czech Republic in the second round of the US Open on Thursday.
IMAGES from Day 6 of the Australian Open in Melbourne, on Saturday.
Defending champions Indian Aces bounced back in style to beat Singapore Slammers 27-20 and record their second successive win in the Japan leg of the International Premier Tennis League (IPTL) season 2 in Kobe.
Garbine Muguruza stormed back into the Grand Slam big time with a 7-5, 6-3 win over Russian Anastasia Pavlyuchenkova to reach her first Australian Open semi-final. Fourth seed Simona Halep advanced to her second Australian Open semi-final with a 6-1, 6-1 demolition of Estonia's Anett Kontaveit in just 53 minutes on Rod Laver Arena.
World number one Angelique Kerber got the birthday gift she wanted Wednesday by making the Australian Open third round, but she had to work hard against fellow German Carina Witthoeft.
The 30-year-old is the first German woman to win Wimbledon since Steffi Graf in 1996.
The top women's seeds continued to be scattered at Wimbledon on Wednesday, with Caroline Wozniacki's exit meaning five of the top eight were gone before the end of the third day.
Venus Williams rallied from the disappointment of losing a tight first set to blast her way past Caroline Garcia 6-7(3), 6-2, 6-3 and set up a WTA Finals title showdown against Caroline Wozniacki on Saturday.
Caroline Wozniacki 0-6, 6-3, 7-5 and advance to the last four at WTA Finals on Friday, the Frenchwoman topping the Red Group after top seed Simona Halep lost later in the day.
Borna Coric ended Roger Federer's 20-match winning streak on grass, beating him 7-6(6), 3-6, 6-2 in the Halle Open final on Sunday while also bringing to a halt the Swiss maestro's reign as World No 1.
Venus Williams gained revenge for her Wimbledon final defeat by Garbine Muguruza when the American advanced to the last four of the WTA Finals with a gutsy 7-5 6-4 victory over the Spanish world number two on Thursday.
Not just because Serena Williams looks capable of landing a 24th Grand Slam title against all the odds having returned from maternity leave and Maria Sharapova is seeking redemption after a 15-month doping ban with a third French Open title.
Dominika Cibulkova kept her hopes of reaching the last four of the WTA Finals alive with a gritty 6-3, 7-6(5) Red Group victory over Simona Halep at the Singapore Indoor Stadium on Thursday.
Angelique Kerber showed more passion in the media centre than on the court when she crashed out of last year's WTA Finals, the German angered by the format and frustrated by her inability to win the set off an eliminated opponent she needed to advance.
Eleven-times champion Rafael Nadal booked his place in the semi-finals of the Barcelona Open semi-finals by beating German Jan-Lennard Struff 7-5, 7-5 in a hard-fought match on Friday.