A day the Australian Open likely feared arrived on Friday, when a COVID-19 outbreak in Melbourne triggered a lockdown in the state of Victoria that will go into effect on Saturday. Serena Williams and Novak Djokovic survived tests in the third round, though Djokovic cautioned he is unsure if he will play in the fourth round after injury.

Australian Open lockdown: Fans ousted for 5 days

The lockdown didn't create the Open's nightmare scenario of a full tournament shutdown thanks to a decision to designate tennis players as essential workers. Play will continue, but starting Saturday, spectators will be barred from the tournament for the next five days.

Up to 30,000 fans had been admitted to Melbourne Park each day at this year's Australian Open, with social distancing and masks requirements in the event of a closed roof. Near-empty stadiums and grandstands had been a common sight so far in the tournament thanks to slow ticket sales, and now they will be totally empty through at least Wednesday.

Australian Open tournament director Craig Tiley told reporters that all fans will be able to receive refunds, including fans who decide to skip Friday's matches. He also said players will play in a bubble format, only moving between their place of residence and the site of the tournament. He doesn't believe the players will have trouble getting a flight home.

The COVID-19 outbreak that caused the lockdown is reportedly located at the Holiday Inn at Melbourne Airport, consisting of 13 cases of the highly infectious UK strain of the virus.

Compared to the United States, Australia has been highly effective in containing COVID-19 so far. As of Thursday, the country had reported only 28,879 COVID-19 cases and 909 deaths total through the pandemic (both numbers are well less than what the U.S. sees in a day), and it's been five months since it has seen more than 50 cases in a day.

Novak Djokovic survives amid muscle tear

No. 1 ranked Novak Djokovic gave it everything he had in the third round to overcome injury and a strong performance by American Taylor Fritz, 7-6(1), 6-4, 3-6, 4-6, 6-2.

Djokovic appeared to suffer a muscle tear in the third set and struggled with his mobility. He said afterward he focused on winning his serves, but struggled on any returns. Fritz, 23, tied the match as Djokovic began to feel better in the fifth.

He called it "one of the most special wins in my life" as he goes for a ninth Australian Open title.

Djokovic cautioned about his future in the tournament. Via The Guardian:

He said he will undergo further evaluation to see what is going on and if he will continue. He faces Milos Raonic in the fourth round and is 11-0 against the Canadian.

Dominic Thiem comes back vs. Nick Kyrgios

The Australian native was so close, but in the end Dominic Thiem brought a stellar comeback to defeat Kyrgios 4-6, 4-6, 6-3, 6-4, 6-4 in the third round. Thiem, the 2020 Australian Open runner-up, has reached the fourth round for the fourth time in five years.

Kyrgios went up two sets and held a 40-15 advantage when Thiem broke the serve for the first time. Thiem said after the match he was "already dealing with the loss" before breaking serve but "then somehow I was fighting myself into the match." Via The Guardian:

Thiem took the 3-0 advantage with the break and continued fighting back to advance. It's the fourth time Thiem has rallied back from two sets down in his career.

Serena Williams capitalizes on opponent's collapse

Serena Williams rarely needs help in the early rounds of Grand Slam tournaments, but she was handed more than a few gifts as she topped Russia's Anastasia Potapova 7-7 (7-5), 6-2 in the third round.

Williams found herself in danger early when Potapova broke her to move up 5-3 with a chance to serve for the first set. Williams had committed 16 unforced errors up to that point, and just didn't look 100 percent. It was reminiscent of her third-round exit in last year's Australian Open.

And then Potapova entered a new frontier of choking. The Russian double-faulted twice to open her pivotal service game, recovered to reach set point, double-faulted again, won again to get another set point, then went double fault, unforced error, double fault to hand Williams one of the most undeserved breaks you will ever see in a Grand Slam.

Williams found life after that and forced a tiebreak, then rolled over a still-struggling Potapova in the second set. At one point, Potapova exited the court while indicating an abdominal problem, but returned minutes later.

The match's "finest" moment might have come on this rally, which was met with gasps from the crowd:

After the win, her 90th in an event she has won seven times,, Williams was in good enough spirits to talk about her three-year-old daughter Olympia, and delivered a pretty great line:

Williams' survival sets up a fourth-round matchup against No. 7 seed Aryna Sabalenka, one of many players in the tournament who idolized Williams growing up.

Naomi Osaka rolls in straight sets, saves ungrateful butterfly

While Williams struggled at times, Naomi Osaka looked like the Australian Open favorite that she is while dispatching No. 27 seed Ons Jabeur 6-3, 6-2 on Friday.

It was vintage Osaka from the three-time Grand Slam champion, dominating with her serve while feasting on Jabeur's second serve. She was much kinder to a butterfly that landed on her during the second set, but had to be very careful when the bug decided to fly onto her face rather than off the court:

With the win, Osaka has now advanced past where she was bounced in the same tournament last year. She is set to face No. 14 seed Garbine Muguruza in the fourth round.

Coco Gauff, Caty McNally upset No. 6 seed in doubles

Teenage sensation Coco Gauff has already been bounced from the women's single draw by No. 5 seed Elina Svitolina, but she stayed alive in doubles on Friday with a big win alongside fellow American Caty McNally.

Together, the teenagers shocked No. 6 seeds Gabriela Dabrowski and Bethanie Mattek-Sands with a 6-1, 6-2 win. Gauff and McNally dominated throughout, committing only four unforced errors against 20 winners.

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