<p>Rafael Nadal stayed on course for a record 21st Grand Slam title at a fan-free Australian Open on Saturday as Ashleigh Barty gave locked-down Melbourne something to cheer.</p>.<p>As Victoria state went into a snap, five-day lockdown to curb a coronavirus outbreak, Daniil Medvedev, Stefanos Tsitsipas and Andrey Rublev all reached the last 16 at an eerily empty Melbourne Park.</p>.<p>But world number one Novak Djokovic, the defending champion and holder of a record eight Australian Open titles, faced a race to be fit for his third-round clash on Sunday.</p>.<p>The Serb, who said he tore an abdominal muscle during Friday's five-set win over Taylor Fritz, skipped training and sought medical advice and treatment on Saturday. He is scheduled to play Canada's Raonic late on Sunday.</p>.<p>The loss of Djokovic, 33, would be another blow for the tournament, reducing the men's 'Big Three' to just one -- Nadal -- with Roger Federer already sidelined by injury.</p>.<p>Nadal, who has his own injury concerns with a stiff lower back, faced down his toughest test so far with a 7-5, 6-2, 7-5 win over British fellow leftie Cameron Norrie.</p>.<p>"The feeling is completely different -- nobody wants this," said Nadal, referring to the 15,000 empty seats that faced him at Rod Laver Arena.</p>.<p>Nadal, 34, will next play colourful Italian Fabio Fognini, who dismissed Australia's Alex De Minaur in straight sets.</p>.<p>Barty, the women's top seed, also said it was "very strange" to play behind closed doors, a day after more than 22,000 fans visited Melbourne Park.</p>.<p>Barty's straightforward 6-2, 6-4 win over Russia's Ekaterina Alexandrova put her into the fourth round without dropping a set as she bids to become the first Australian winner since Chris O'Neil in 1978.</p>.<p>"It's very strange, it changes the sound in the court a little bit," Barty said of the empty, 7,500-seat Margaret Court Arena.</p>.<p>"It kind of felt a little bit like practice," she added.</p>.<p>Players were ordered into a biosecure "bubble" during the lockdown, just the latest coronavirus disruption for a tournament that was pushed back three weeks to allow for quarantines.</p>.<p>The Australian Open, the biggest international sports event so far this year, is seen as a test case for the Tokyo 2020 Olympics, which are scheduled to start in July after a year's delay.</p>.<p>As play unfolded in the empty arenas, former world number one Karolina Pliskova had a racquet-smashing tantrum en route to a 7-5, 7-5 defeat by fellow Czech Karolina Muchova.</p>.<p>Ukrainian fifth seed Elina Svitolina beat Yulia Putintseva 6-4, 6-0, and Russia's men's fourth seed Medvedev overcame buttock pain and a mid-match lapse in his 6-3, 6-3, 4-6, 3-6, 6-0 win over Filip Krajinovic of Serbia.</p>.<p>"It's a different atmosphere, different vibe," said Greek world number six Tsitsipas, after his 6-4, 6-1, 6-1 win over Mikael Ymer.</p>.<p>"But if I can win my next matches, the crowd will be back. It's just five days, and I'll be happy to see them back."</p>.<p>Tsitsipas beat Ymer in a silent John Cain Arena -- which had been packed with thousands of noisy fans late on Friday for Australian player Nick Kyrgios's defeat by Dominic Thiem.</p>.<p>In the same venue, Matteo Berrettini beat Russian seed Karen Khachanov 7-6 (7/1), 7-6 (7/5), 7-6 (7/5) to set up a meeting with Tsitsipas.</p>.<p>"I really miss the crowd, I have to be honest," said the Italian.</p>.<p>"Looking at a stadium like this and seeing it empty is not the best feeling. But we're living in really tough times."</p>.<p>Elsewhere Russia's Rublev ended Spanish veteran Feliciano Lopez's record 75th consecutive Grand Slam to set up a meeting with Norway's Casper Ruud.</p>
<p>Rafael Nadal stayed on course for a record 21st Grand Slam title at a fan-free Australian Open on Saturday as Ashleigh Barty gave locked-down Melbourne something to cheer.</p>.<p>As Victoria state went into a snap, five-day lockdown to curb a coronavirus outbreak, Daniil Medvedev, Stefanos Tsitsipas and Andrey Rublev all reached the last 16 at an eerily empty Melbourne Park.</p>.<p>But world number one Novak Djokovic, the defending champion and holder of a record eight Australian Open titles, faced a race to be fit for his third-round clash on Sunday.</p>.<p>The Serb, who said he tore an abdominal muscle during Friday's five-set win over Taylor Fritz, skipped training and sought medical advice and treatment on Saturday. He is scheduled to play Canada's Raonic late on Sunday.</p>.<p>The loss of Djokovic, 33, would be another blow for the tournament, reducing the men's 'Big Three' to just one -- Nadal -- with Roger Federer already sidelined by injury.</p>.<p>Nadal, who has his own injury concerns with a stiff lower back, faced down his toughest test so far with a 7-5, 6-2, 7-5 win over British fellow leftie Cameron Norrie.</p>.<p>"The feeling is completely different -- nobody wants this," said Nadal, referring to the 15,000 empty seats that faced him at Rod Laver Arena.</p>.<p>Nadal, 34, will next play colourful Italian Fabio Fognini, who dismissed Australia's Alex De Minaur in straight sets.</p>.<p>Barty, the women's top seed, also said it was "very strange" to play behind closed doors, a day after more than 22,000 fans visited Melbourne Park.</p>.<p>Barty's straightforward 6-2, 6-4 win over Russia's Ekaterina Alexandrova put her into the fourth round without dropping a set as she bids to become the first Australian winner since Chris O'Neil in 1978.</p>.<p>"It's very strange, it changes the sound in the court a little bit," Barty said of the empty, 7,500-seat Margaret Court Arena.</p>.<p>"It kind of felt a little bit like practice," she added.</p>.<p>Players were ordered into a biosecure "bubble" during the lockdown, just the latest coronavirus disruption for a tournament that was pushed back three weeks to allow for quarantines.</p>.<p>The Australian Open, the biggest international sports event so far this year, is seen as a test case for the Tokyo 2020 Olympics, which are scheduled to start in July after a year's delay.</p>.<p>As play unfolded in the empty arenas, former world number one Karolina Pliskova had a racquet-smashing tantrum en route to a 7-5, 7-5 defeat by fellow Czech Karolina Muchova.</p>.<p>Ukrainian fifth seed Elina Svitolina beat Yulia Putintseva 6-4, 6-0, and Russia's men's fourth seed Medvedev overcame buttock pain and a mid-match lapse in his 6-3, 6-3, 4-6, 3-6, 6-0 win over Filip Krajinovic of Serbia.</p>.<p>"It's a different atmosphere, different vibe," said Greek world number six Tsitsipas, after his 6-4, 6-1, 6-1 win over Mikael Ymer.</p>.<p>"But if I can win my next matches, the crowd will be back. It's just five days, and I'll be happy to see them back."</p>.<p>Tsitsipas beat Ymer in a silent John Cain Arena -- which had been packed with thousands of noisy fans late on Friday for Australian player Nick Kyrgios's defeat by Dominic Thiem.</p>.<p>In the same venue, Matteo Berrettini beat Russian seed Karen Khachanov 7-6 (7/1), 7-6 (7/5), 7-6 (7/5) to set up a meeting with Tsitsipas.</p>.<p>"I really miss the crowd, I have to be honest," said the Italian.</p>.<p>"Looking at a stadium like this and seeing it empty is not the best feeling. But we're living in really tough times."</p>.<p>Elsewhere Russia's Rublev ended Spanish veteran Feliciano Lopez's record 75th consecutive Grand Slam to set up a meeting with Norway's Casper Ruud.</p>