Serena Williams crashed out, 15-year-old Coco Gauff stunned Naomi Osaka and Roger Federer survived a five-set thriller as the form book went flying out of the window at the Australian Open on Friday.

Men’s title-holder Novak Djokovic eased into the last 16 but
elsewhere there were surprises all over Melbourne Park with Williams the
biggest victim and Federer fighting back from 4-8 down in a fifth-set tie-break
with John Millman.

Williams’ bid for a record-equalling 24th Grand Slam was
shattered by the unlikely figure of China’s Wang Qiang, who triumphed in three
tough sets — after winning just one game when they played at the US Open in
September.

Gauff then stepped up her giant-killing Melbourne debut as
she ousted Japanese defending champion Osaka, 22, in dismissive style, winning
6-3, 6-4 in just 67 minutes to reach round four.

“Oh my gosh. Two years ago I lost first round in the
juniors and now I’m here — this is crazy,” said the teenager, who shocked
Venus Williams in the first round.

Federer came within a whisker of repeating his 2018 US Open
upset by Millman as he was taken to five punishing sets by the tough
Australian.

The 20-time Grand Slam champion was facing defeat in the
super tie-breaker but he clawed back from 4-8 down to clinch his 100th win at
the Australian Open.

“Oh God, it was tough,” said Federer. “Thank
God it was a super tie-breaker (10 points), otherwise I would have lost this
one. It came down to the wire in the end.”

‘I made it happen’

With Williams now 38, 23 years older than Gauff, the two
players are at opposite ends of their careers.

And with Williams’ close friend Caroline Wozniacki retiring
on Friday, after defeat to Ons Jabeur, it looked like a changing of the guard
in women’s tennis.

But Williams, who has now had eight winless Grand Slams
since returning from childbirth, said she hadn’t given up hope of matching
Margaret Court’s 47-year-old record for Grand Slam titles.

“I definitely do believe (I can equal it) or I wouldn’t
be on tour,” said Williams.

Williams was the bookies’ favourite to lift the trophy for
the eighth time but she came unstuck against a determined Wang, who won 6-4,
6/7 (2/7), 7-5.

Her defeat came just minutes after Denmark’s Wozniacki was
knocked out by Tunisia’s Jabeur, bringing a tearful end to the former world
number one’s final tournament before retiring.

“I had a dream when I was a kid. I wanted to win a
Grand Slam. I wanted to be number one in the world,” said Wozniacki, the
Melbourne winner in 2018. “People thought that I was crazy being from a
small country. But I made it happen.”

Rattled Osaka

Williams’ exit removes a major hurdle for Australia’s world
number one Ashleigh Barty, 23, who had been on course to meet her in the
semi-finals.

Barty, bidding to become the first Australian champion since
1978, hit form in a 6-3, 6-2 demolition of Elena Rybakina, saying she had
played her best tennis so far this year.

Gauff, who trained with Serena Williams in the off-season,
had promised she would be less nervous than in her last meeting with Osaka,
when she was thrashed in round three of last year’s US Open.

And so it proved as the teenager broke once in the first set
and twice in the second to floor a rattled Osaka and ramp up a rivalry that
could run and run.

In the men’s draw, reigning champion Djokovic thrashed
Japan’s Yoshihito Nishioka 6-3, 6-2, 6-2 to reach the round of 16 at a canter.

But Greek sixth seed Stefanos Tsitsipas was also on the
receiving end of an upset as he went down in straight sets to Canada’s Milos
Raonic, the world number 35.

Former US Open champion Marin Cilic, 31, outlasted Robert
Bautista Agut in five tough sets and Tennys Sandgren, under fire during his
last deep run in Melbourne over links to right-wing activists, beat fellow
American Sam Querrey in straight sets.