Serena Williams suffered a major injury scare just minutes into her bid for a calendar-year Grand Slam on Tuesday, while Andy Murray opened his account in majestic style at the Australian Open.
Williams, gunning for the first sweep of all four major titles in the same year since 1988, was on court for only 19 minutes against Edina Gallovits-Hall before going over heavily on her right ankle.
However, after medical treatment and despite hobbling around the court, the 15-time Grand Slam-winner astonishingly won 6-0, 6-0 in just 54 minutes as she belted every winner in sight to limit her running to a minimum.
Afterwards, the 31-year-old said she felt pain and swelling and may need an x-ray, but she pledged to soldier on in the next round.
"Oh, I'll be out there. I mean, unless something fatal happens to me, there's no way I'm not going to be competing," she said. "I'm alive. My heart's beating. I'll be fine."
She added: "Obviously there's pain. Obviously there's swelling. So it's going to be really important to see how the next few hours unfold."
Any lasting injury to the hot favourite could throw the women's draw wide open and may benefit defending champion Victoria Azarenka, who is scheduled to meet Williams in the semi-finals.
The world number one beat Romania's Monica Niculescu to reach the second round, but had to come from 3-0 down in the second set before winning 6-1, 6-4.
Caroline Wozniacki, last year's top seed and now ranked at world number 10, also had to dig deep before reeling off six third-set games in a row to beat Germany's Sabine Lisicki.
"Today I had to get my fighting spirit up and fight back, and it paid off. It's a new year and a new tournament and that's basically all I think about," Wozniacki said.
Former Wimbledon champion Petra Kvitova also won but Italy's seventh seed Sara Errani, who contested last year's French Open final, became the biggest casualty so far when she crashed out to Carla Suarez Navarro.
Elsewhere Japanese number one Kimiko Date-Krumm, aged 42, became the oldest female to win a main draw match at the Australian Open, upsetting 12th seed Nadia Pedrova 6-2, 6-0, 12 years her junior.
In the men's draw, Murray was first up on Rod Laver Arena and, in his first Grand Slam match since becoming a major-winner, showed his class in a 6-3, 6-1, 6-3 dismantling of Dutchman Robin Haase.
Murray, who used iced towels during breaks to counter the rising heat, said he hoped the experience of September's US Open win would help him later in the tournament. The Scot is drawn to face Roger Federer in the semi-finals.
"It didn't feel much different to me. I was still nervous before I went on to play the match," Murray said.
"I think when I would see the benefits of that is if I get myself deep into a Slam this year and you're playing against the top players. That's when I think you'll draw on that experience and use it in the right way."
Murray was also among a group of players and officials to pay tribute to ATP chief Brad Drewett, who announced that he was stepping down from the post after being diagnosed with motor neurone disease.
"It's obviously very shocking news. Very sad. He's done a very good job for the tour," said the world number three.
"He's done a good job of bringing the tournaments together and arranging the meetings we had with the slams. He's definitely had an impact in the time he's been working there.
"It's a big shame to hear something like that happen. Hope he's okay."