Serena Williams made serene progress in her bid for a record-equaling 24th Grand Slam title while eight-time champion Novak Djokovic was made to sweat at the Australian Open on Wednesday.
Women's favorite Naomi Osaka also charged through but fellow major-winners Stan Wawrinka, Bianca Andreescu and Petra Kvitova were all second-round casualties.
Djokovic was given a stern examination by the U.S.' Frances Tiafoe and dropped his first set of the tournament before recovering to win 6-3, 6-7 (3/7), 7-6 (7/2), 6-3.
"I was fortunate to get through the third set today, it was anybody's game," said the defending champion, after his win in hot conditions on Rod Laver Arena.
The top seed looked in control after taking the first set, but lightning-quick Tiafoe, who reached the quarterfinals two years ago, refused to go quietly.
The American bounced back to take a close second set but imploded as tensions rose in the fourth, receiving a code violation for an audible obscenity as Djokovic took charge.
"I thought we both played on a pretty high level. I mean, he pushed me to the very limit," said Djokovic.
The Serb is targeting a record-extending ninth title and his 18th Grand Slam trophy overall as he snaps at the heels of Rafael Nadal and Roger Federer, who top the all-time list with 20 each.
He avoided the fate of 2014 winner Wawrinka, who blew three match points in the fifth-set tiebreaker in his four-hour epic with Marton Fucsovics, who won 7-5, 6-1, 4-6, 2-6, 7-6 (11/9).
"I had some chance to finish the match, I didn't finish," said the 35-year-old Swiss, a three-time Grand Slam winner.
"I hesitated a little bit when I had the match point and I lost it," he said.
Osaka, whose three Grand Slam titles include the 2019 Australian crown, had no such trouble in her evening match against France's Caroline Garcia, winning 6-2, 6-3 in 61 minutes.
Earlier Williams, 39, continued her quest to equal Margaret Court's all-time mark of 24 Grand Slams with a 6-3, 6-0 romp past 99th-ranked Serbian Nina Stojanovic.
Williams hit 27 winners in her 101st Australian Open match while again sporting her unique, one-legged catsuit inspired by track legend "Flo-Jo."
"I'm here to have fun and it's great to be playing in front of a crowd," said the American great.
Second seed Simona Halep was rattled by big-hitting Alja Tomljanovic, but won five games in a row to survive a major scare and reach the Australian Open third round.
The two-time Grand Slam winner was pushed to the brink by the gutsy Australian in a see-saw second-round clash before finally prevailing 6-4, 4-6, 7-5 in two hours and 34 minutes.
With Australia virtually virus-free, the tournament is welcoming the biggest Grand Slam crowds since the pandemic, although attendance is well down from previous years.
Williams' elder sister Venus, 40, was a major casualty on day three when she painfully rolled her ankle in the first set against Sara Errani before hobbling through a 6-1, 6-0 defeat.
And Andreescu, the 2019 U.S. Open champion who missed the entire 2020 season with a knee injury, saw her comeback come to an abrupt end 6-3, 6-2 against Taiwan's Hsieh Su-wei.
"You need to find a way to get through and the crowd helped me fight," said Hsieh after beating the Canadian, who was coming off a draining three-setter against Mihaela Buzarnescu.
Elsewhere Kvitova, the former Wimbledon champion and Melbourne runner-up in 2019, committed 44 unforced errors in her 6-4, 1-6, 6-1 defeat to Romania's Sorana Cirstea as the big names tumbled on day three.
However, reigning U.S. Open champion Dominic Thiem, runner-up to Djokovic last year, was all smiles as he beat Germany's Dominik Koepfer 6-4, 6-0, 6-2.
"It was great, to be honest," Thiem said of his performance on Margaret Court Arena.
Eighth seed Diego Schwartzmann of Argentina also hurried into the last 32, brushing aside Frenchman Alexandre Muller 6-2, 6-0, 6-3 in an hour and 32 minutes on 1573 Arena.
Meanwhile, volatile Australian Nick Kyrgios smashed a racquet, delivered underarm serves, ranted at the umpire and saved two match points on his way into the Australian Open third round.
The 25-year-old drew a raucous, socially distanced crowd to his favored John Cain Arena and kept them highly entertained, with the atmosphere electric in a gripping clash with Frenchman Ugo Humbert.
He eventually came through 5-7, 6-4, 3-6, 7-6 (7/2), 6-4 after 3 hours 25 minutes against the 29th seed to set up a blockbuster clash with third seed Dominic Thiem.