World number one Ash Barty has been knocked out of the Charleston Open after a straight-sets loss to unseeded Spaniard Paula Badosa in Friday's quarter-finals.

Badosa won 6-4 6-3 over the favoured Australian in one hour, 16 minutes to book a spot in the last four on the green clay and a meeting with 15th seed Veronika Kudermetova.

Kudermetova beat 2017 US Open winner Sloane Stephens 6-3 6-4 in her first win over a grand slam winner.

Former French Open junior champion Badosa, who beat fifth seed Belinda Bencic in the second round, claimed her second career victory over a top-20 player against Barty.

Barty may have hit 34 to 19 winners but she also made twice as many unforced errors, 24 to 12.

The Spaniard broke Barty's serve five times while she sent down seven aces and saved 12 of 14 break points.

"I was quite nervous today but I think I served very well and I think that was the key for the match," Badosa said in her on-court interview.

"It was a tough match but I was there until the last moment and I managed to win."

World number 71 Badosa becomes the lowest-ranked player to beat Barty since September 2019.

The Australian had won eight matches in a row after last week's triumph at the Miami Open.

Unseeded Montenegrin Danka Kovinic came from a set down to topple 11th seed Yulia Putintseva 6-7 (2-7) 7-5 6-1.

Kovinic, who knocked out Petra Kvitova in the third round, will play 12th seed Ons Jabeur in the semi-finals after she overcame Coco Gauff 6-3 6-3.

Meanwhile, at the Copa Colsanitas in Bogota, fifth Tamara Zidansek beat Italy's Sara Errani 6-3 6-4 to claim a spot in the semi-finals.

Viktoriya Tomova outlasted qualifier Nuria Parrizas-Diaz 5-7 6-2 6-4 in almost two and a half hours, while Harmony Tan and local wildcard Maria Camila Osorio Serrano also won.

Ash Barty may have her focus on winning the Australian Open right now but suggested a career change could be on the cards in the future.  

The world number one made sure she will still be competing during the second week of the tournament in Melbourne by beating Ekaterina Alexandrova in straight sets.  

But, having played international cricket for Australia before switching to tennis, could the multi-talented Barty be considering trying another sport?  

Elsewhere in Saturday's action, Karolina Pliskova lost her cool – and also a couple of rackets – as she slipped to defeat against the impressive Karolina Muchova in an empty Rod Laver Arena, with fans not able to be present due to a five-day lockdown in the state of Victoria.

Elina Svitolina had no such problems in her third-round match, while Elise Mertens was victorious in just over an hour against Belinda Bencic. Jennifer Brady ended Slovenian qualifier Kaja Juvan's run in the first grand slam of the year.

AUSSIE RULES, OK? 

After winning 6-2 6-4 without ever needing to be at her peak, Barty was cheekily asked by former doubles partner Casey Dellacqua – now working in the media – whether she may be set to switch paths again, once her tennis career has come to an end.  

Australian rules football was the answer – but Dellacqua maybe got more than she bargained for from her former playing partner during the on-court interview. 

"I thought it was our deal, we're going to AFLW. It's ABCD [the nickname for the pairing from their doubles career]. We come as a package, and I know we will be going to the [Richmond] Tigers that is for sure," Barty said. "You can't go to Carlton. You have to come to the 'Tiges' with me."

Dellacqua replied: "I need to get out there and start practicing some kicking, but you are good. I would love to do that one day." 

For Barty, though, the next challenge facing her is Shelby Rogers, who knocked out 21st seed Anett Kontaveit during the evening session.  

MAKING A RACKET 

A disgruntled Pliskova was not impressed when punished for smashing up a racket during her match with compatriot Muchova. 

Having received a warning when throwing a racket to the floor during the course of the final game in the opening set, the sixth seed then vented her frustration again on another while in the players' tunnel.  

An official witnessed the incident and reported it to chair umpire Alison Hughes, who punished the Czech with a point penalty before she began serving to open the second set.  

"It's off court, I'm allowed to do what I want," Pliskova insisted when querying the decision to the official. She would go on to hold before recording two successive breaks, yet somehow failed to force a decider.  

Muchova rallied from 5-0 down in sensational fashion, winning seven games on the spin to triumph 7-5 7-5 to make it through to the last 16.

CONTRASTING PROGRESS FOR SEEDS

Svitolina has still yet to drop a set in the tournament after overcoming 26th seed Yulia Putintseva by a 6-4 6-0 scoreline.  

The fifth seed was twice down a break in the first set but, after eventually coming out on top to take a 1-0 lead, breezed through the second in a hurry.  

"She has a very different game style from what I played my last two rounds, so it wasn't easy at the beginning to adjust," Svitolina said. "As soon as I was feeling better, I just stepped my game, and it was quite a comfortable win after." 

Next up will be Jessica Pegula, who is through to the fourth round at a slam for the first time in her career after thrashing Kristina Mladenovic 6-2 6-1.  

There was also success for another American in the main draw, Brady defeating Juvan in straight sets. Her reward is a clash with Donna Vekic, the 28th seed having to save a match point before eventually seeing off Kaia Kanepi 5-7 7-6 (7-2) 6-4 after two hours and 38 minutes on court. 

Elina Svitolina said playing behind closed doors at the Australian Open felt "a bit disturbing" after having fans in attendance earlier in the week.

The Ukrainian fifth seed booked her spot in the fourth round in Melbourne with a 6-4 6-0 victory over Yulia Putintseva on Saturday.

But no fans were in attendance on Margaret Court Arena as Victoria started a five-day lockdown due to coronavirus.

Svitolina, who will face Jessica Pegula in the last 16, said she felt the difference.

"It was very different conditions. I played a night match at 7:00 with a good crowd. Now it was completely different. It was for sure a bit disturbing, I would say, in some ways sad," she told a news conference.

"But it is what it is. I had to accept. I had to have a good mindset, not thinking too much about that. I just tried to focus on my game."

Svitolina reached the fourth round in Melbourne for the third time in four years after mixing 18 winners with 20 unforced errors.

But the 26-year-old said the lack of fans meant the third-round encounter felt like a practice match.

"It feels like that. I actually had few thoughts about it today. It feels like this. I tried to convince myself that it's a grand slam and that we are playing an important match. I have to focus on my match," Svitolina said.

"But for sure there's some thoughts and there is I say some low moments that can sneak into the mind. It's what we have to deal with. I'm trying my best to do it."

Sofia Kenin and Elina Svitolina fought back from the brink of defeat as both reached the Abu Dhabi Women's Tennis Open quarter-finals on Sunday.

Top seed Kenin fended off a match point in the second set before battling to a 3-6 7-6 (7-5) 6-4 victory over Yulia Putintseva at Zayed Sports City International Tennis Centre.

Putintseva was serving for a straight-sets win at 6-5 up in the second, but the tenacious Kenin forced a tie-break and rallied from 3-1 down to take the third-round match the distance.

The Australian Open champion secured three breaks in the decider to reach the last eight, hitting 35 winners to 25 from 13th seed Putintseva to set up a showdown with Maria Sakkari.

Svitolina, the second seed, was also on the verge of crashing out, but she hung in there to pull off a 6-2 6-7 (5-7) 7-6 (10-8) win over Ekaterina Alexandrova.

The world number five was a break down in the final set and saved two match points in a tense tie-break before finally seeing the back of her Russian opponent.

Ninth seed Sakkari beat two-time grand slam champion Garbine Muguruza 7-5 6-4 to give herself the opportunity to get the better of Kenin for the first time in three attempts.

Aryna Sabalenka stretched her impressive winning streak to 12 matches with a 6-2 6-4 success over Ons Jabeur, while Marta Kostyuk, Sara Sorribes Tormo, Elena Rybakina and Veronika Kudermetova also progressed.

Veronika Kudermetova started the new season in style by beating 10th seed Anett Kontaveit in the first round of the Abu Dhabi Women's Tennis Open on Wednesday.

Kudermetova had won her only two previous singles matches against Kontaveit and maintained that perfect record with a 7-5 6-1 victory.

The world number 46 from Russia broke four times to seal her place in the second round, with Kontaveit winning just 48.4 per cent of points on her first serve in a rusty beginning to the 2021 campaign.

Donna Vekic was another seed to fall at the first hurdle as Bernarda Pera consigned the Croatian to a 7-6 (12-10) 2-6 6-4 defeat at Zayed Sports City International Tennis Centre.

Kirsten Flipkens could face top seed Sofia Kenin in the second round after defeating Laura Siegemund 5-7 7-5 6-4.

Ons Jabeur is aiming to break into the top 10 this year and the 15th seed got up and running for the season by seeing off Anastasia Pavlyuchenkova 7-6 (7-3) 6-3.

Daria Kasatkina, Yulia Putintseva and Ajla Tomljanovic were among the other players who advanced to round two.