Melbourne (AFP) - Rafael Nadal steps up his march towards a record 21st Grand Slam title at the Australian Open on Wednesday, with Ashleigh Barty and Naomi Osaka also taking centre stage.
Defending champion Osaka and Wimbledon winner Barty will be one victory away from colliding if both come through their second-round encounters unscathed.
Japan's Osaka, who has won two Australian and two US Opens, faces American Madison Brengle in the night session on Rod Laver Arena.
Red-hot Barty, the top seed and home hope, comes up against Italian qualifier Lucia Bronzetti in an early afternoon encounter.
Nadal, who recently won his first tournament after five months out battling a foot injury, was highly impressive in racing past American Marcos Giron in straight sets on Monday to open his campaign.
"I am super-happy about all the work that we have done to try to be back.We are here enjoying the tennis," said the Spanish sixth seed, who will face German qualifier Yannick Hanfmann after Barty's match ends.
Nadal's half of the draw was made easier when the unvaccinated nine-time champion Novak Djokovic was thrown out of Australia.
In the mood
The ultra-consistent Barty, who won a warm-up tournament in Adelaide, hasn't dropped her serve for 41 straight games over four matches and destroyed Lesia Tsurenko 6-0, 6-1 on Monday.
"I think obviously the last five or six matches I felt like I found a really good rhythm on my service games," said the Australian, who is chasing a first home Grand Slam.
Osaka beat American Jennifer Brady in last year's Melbourne Park final, but then withdrew from the French Open and Wimbledon over mental health issues.She took an indefinite break after the US Open in September.
But the 24-year-old said she felt much more positive after her first-round win over Colombia's Camila Osorio.
"I just want to have fun, first of all," said the 13th seed.
"I can't expect myself to win every match, but I do expect myself to have fun and challenge myself."
Men's third seed Alexander Zverev is looking to follow his Olympic gold in Tokyo last year with a first Grand Slam title.
He safely came through a tricky late-night first-round clash against fellow German Daniel Altmaier despite not being at his best.
"It's the first round of hopefully a very long Grand Slam, you are not always going to play your best tennis," said the 24-year-old.
He will play Australia's John Millman, who will garner plenty of partisan vocal support in another late-night encounter on Rod Laver Arena.
French Open champion Barbora Krejcikova was ruthless in her dismissal of German veteran Andrea Petkovic 6-2, 6-0 in the first round, and a repeat of that form should see her past China's world number 100 Wang Xiyu.
Spanish eighth seed Paula Badosa, who beat Krejcikova in a three-set thriller to win the Sydney warm-up tournament, opens proceedings at 11:00am (0000 GMT) against Italian qualifier Martina Trevisan.
On the men's side, seventh seed Matteo Berrettini, who endured frequent toilet trips in a gutsy four-set win on Monday, will hope he doesn't need to reach for the Imodium again when he comes up against American qualifier Stefan Kozlov.
