Australia's Ellen Perez has painted a troubling picture for the dozens of players competing at the Australian Open, who were forced into hard lockdown before the tournament.
The World No.237 was one of 73 players confined to their Melbourne hotel rooms and unable to come out and train for 14 days.
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While some of the sport's biggest stars such as Novak Djokovic, Rafael Nadal, Serena Williams and Naomi Osaka enjoyed the benefits of being able to train outside during quarantine in Adelaide, Perez and others were forced to do it much tougher.
Perez only got out of hotel quarantine at 1230 on Wednesday morning and headed straight to Rod Laver Arena for her first hit in 14 days.
She then tried to play her first match against American Ann Li in the Grampions Trophy - reserved for female players who had been in hard lockdown - but was forced out with a back injury while trailing 5-3.
"Overnight after my hitting it stiffened up but I wanted to give myself a chance so I warmed up and thought maybe I could get through the match but it was something that got worse," said Perez, the world No.237.
"I've always had chronic back pain ... but going from zero to 100 it's really flared up."
Perez also had to go through hard lockdown in Perth late last year after returning home from the French Open.
The Aussie's first match upon her return on that occasion resulted in her suffering an abdominal strain.
The 25-year-old says based on her own experiences, she thinks it's highly unlikely that any of the Australian Open contingent who underwent hard lockdown, can seriously challenge for the grand slam title.
That list of players includes grand slam champions Bianca Andreescu, Victoria Azarenka and Angelique Kerber, while the highest profile male player is Japan's Kei Nishikori.
World No.8 Andreescu, who won the US Open in 2019, pulled out of the tournament to try to get more training under her belt.
"I think we are at a disadvantage - you've got very limited days and each day really does make a difference," said Perez, who will play doubles at the Open.
"It's extremely tough to go through that lockdown and maintain that repetition and same intensity.
"You can't strike a ball or practice serves so everything stiffens up."
She said the men, who play best of five sets in the majors, would particularly struggle.
"For the men, I can't see how they're going to manage to be able to pull up from a five-set match and back it up.
"The women may struggle a bit less but I definitely wouldn't want to be in that position, trying to go deep having come out of lockdown."
Barty returns with a bang
Although not one those stars forced into hard lockdown, Ash Barty showed signs of fatigue in her tough three-set win over Czech Marie Bouzkova on Wednesday.
After a near year-long hiatus, Australia's world No.1 advanced to the quarter-finals in her first tournament back with a 6-0 4-6 6-3 victory.
Barty has not been sighted on tour since a semi-final loss to Petra Kvitova last February.
She didn't disappoint on Wednesday, however, surviving a stern two-hour test of her nerve to progress to the last eight of the Yarra Valley Classic.
The 24-year-old breezed through the opening set without dropping a game, then recovered from losing the second and retained her cool in a topsy-turvy deciding set to prevail.
Barty will play American Shelby Rogers in the last eight and could potentially face Williams in the semi-finals.
Naomi Osaka also overcame a gruelling three-set test against Brit Katie Boulter - booking a quarter-final berth in the Melbourne Summer Series event with a 3-6 6-3 6-1 victory.
Osaka stepped up her game after a low-key start and showed her championship qualities with some heavy ground strokes and damaging serving proving decisive.
Boulter, who is ranked 371st but playing on a protected ranking due to a run of injuries, impressed but couldn't go with the US Open champion in the deciding set.
After only conceding four games in her opening match against Alize Cornet, Osaka said being forced to scramble from a set down was ideal.
"I couldn't have asked for a better preparation match,"the 23-year-old Japan superstar said.
I think it was very different from my first-round match and that's something I couldn't practise.
"I can't practise a match like this so I'm very happy with how it went actually.
"Even though it was long, I think there are a lot of things that I learned."
Reigning champion Sofia Kenin didn't have it all her own way against fellow American Jessica Pegula, scrambling to a 5-7 7-5 6-2 win.
British No.1 Johanna Konta, the world No.14. was ousted after a marathon battle against Irina-Camelia Begu 4-6 7-6 (10-8) 7-6 (6-4).
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