Stefanos Tsitsipas struck a huge blow for the next generation by beating two-time defending champion Roger Federer in the fourth round of the Australian Open.

Tsitsipas next faces another first-time grand slam quarter-finalist in Roberto Bautista Agut while Rafael Nadal eased past Tomas Berdych and will take on Frances Tiafoe, who celebrated his 21st birthday with an emotional win over Grigor Dimitrov.

Ashleigh Barty became the first Australian woman to reach the last eight here for a decade by knocking out Maria Sharapova and next plays Petra Kvitova while American Danielle Collins stunned second seed Angelique Kerber for the loss of only two games.

Picture of the day

Stefanos Tsitsipas looks stunned after beating Roger Federer
Stefanos Tsitsipas looks stunned after beating Roger Federer (Mark Schiefelbein/AP)

Tweet of the day

Greece’s other leading player gives her reaction.

Frances and the king

LeBron James gave his verdict on Tiafoe’s celebration (Instagram)

Tiafoe has been copying his hero, basketball superstar LeBron James, with his celebrations this week, removing his shirt to thump his bare chest and his biceps. When ESPN put both versions on their Instagram page, who should reply but James himself.

“He commented ‘silencer’ (the name of the celebration) and he put a crown, two muscle emojis,” said Tiafoe. “I was like, ‘Clearly he knows who I am now. That’s just crazy’.”

Collins up for the fight

Danielle Collins likes making tennis 'a war'
Danielle Collins likes making tennis ‘a war’ (Kin Cheung/AP)

Collins has come to wider attention thanks to her stunning run here but anyone who has seen the American on a court knows that feistiness is her stock in trade.

She said: “I love making it kind of a war. If somebody wants to get in my face on my unforced errors, I have no problem getting right back at them. I just love competition. Sometimes when people are all for me I’m like, ‘I hope somebody says something negative so I can prove them wrong’.”

Fallen seeds

Women: Angelique Kerber (2), Sloane Stephens (5), Maria Sharapova (30)

Men: Roger Federer (3), Marin Cilic (6), Grigor Dimitrov (20)

Who’s up next?

Simona Halep, right, will attempt to follow up her victory over Venus Williams by knocking out Serena
Simona Halep, right, will attempt to follow up her victory over Venus Williams by knocking out Serena (Kin Cheung/AP)

The big match on Monday sees title favourite Serena Williams go up against world number one Simona Halep in the first match of the night session on Rod Laver Arena.

Following that, Novak Djokovic will look to avoid suffering the same fate as Federer when he takes on talented young Russian Daniil Medvedev.

Earlier, US Open champion Naomi Osaka faces Anastasija Sevastova while fourth seed Alexander Zverev will look to reach only his second slam quarter-final against in-form Milos Raonic.