American Learner Tien kept the teenage revolution going at the Australian Open by reaching the last 16 on Saturday after 38-year-old Gael Monfils had made a statement for the older player with a stunning upset of fourth seed Taylor Fritz.

Tien, 19, took out hobbling Frenchman Corentin Moutet 7-6(10) 6-3 6-3 to continue his stunning run on his Melbourne Park debut and become the youngest man to reach the fourth round at the Australian Open since Rafa Nadal in 2005.

The American ousted fifth seed Daniil Medvedev in the early hours of Friday morning but showed no signs of wear and tear from that five-set epic as he set up a clash against Lorenzo Sonego.

“It feels great, obviously,” said the Californian. “This exceeded my expectations coming into this week, you expect to win every match but to be in the second week is amazing.”

Italian Sonego beat Fabian Marozsan 6-7(3) 7-6(6) 6-1 6-2 to book his spot in the fourth round, having ended the campaign of Brazilian 18-year-old Joao Fonseca in the second round.

Tien, Fonseca and 19-year-old Czech Jakub Mensik tore up the form guide by dumping top ten seeds out in the first week, heralding the rise of a new generation to threaten the dominance of early twentysomethings Carlos Alcaraz and Jannik Sinner.

Novak Djokovic, at 37, is still flying the flag for the golden generation in the fourth round and Frenchman Monfils joined him by coming from a set down to beat Fritz 3-6 7-5 7-6(1) 6-4, celebrating with a jig.

“I keep playing for those matches,” said Monfils. “Play big players, big stadiums, good crowd, good energy. When you’re 38-years-old, that’s what I want. I had it. I was very fortunate to win it.”

There was no glimmer of an upset earlier when women’s second seed Iga Swiatek charged into the fourth round with a 6-1 6-0 humbling of Emma Raducanu in a meeting of former US Open champions.

“I just enjoyed playing, I played a few shots where I thought ‘yeah, this is what I practised for’,” said the 23-year-old, who has yet to drop a set.

Swiatek will next face Eva Lys, who became the first lucky loser to reach the women’s fourth round since 1988 after beating Romanian Jaqueline Cristian 4-6 6-3 6-3.

Alex Michelsen is only five months out of his teens and he continued his stellar start to the tournament with a quickfire 6-3 7-6(5) 6-2 win over Karen Khachanov.

The 20-year-old American, who upset Stefanos Tsitsipas in the first round, had to hang tough to battle back from 3-0 down in the second set against the 2023 semi-finalist before getting the job done on John Cain Arena.

Michelsen, Fritz and Marcos Giron, who later faces defending champion Sinner, were among five Americans hoping to join compatriot Tommy Paul in the fourth round on Saturday.

Alex de Minaur has few peers when it comes to hanging tough and he kept the Australian flag flying into the second week after battling his way to a 5-7 7-6(3) 6-3 6-3 victory over Argentine Francisco Cerundolo on a packed Rod Laver Arena.

“You put in a lot of hard work in the off season and these are the results,” said the men’s eighth seed.

“Something you can always count on, even if I don’t win, I will always fight to the end.”

Women’s eighth seed Emma Navarro earlier joined the American charge with a 6-4 3-6 6-4 win over Tunisian Ons Jabeur in a topsy-turvy match on Margaret Court Arena.

Next up for Navarro is Russian Daria Kasatkina, who downed Kazakh Yulia Putintseva 7-5 6-1 on Kia Arena to reach the second week for the first time on her 10th trip to Melbourne Park.

Putintseva’s compatriot Rybakina needed seven match points to close out her 6-3 6-4 win over Ukraine’s Dayana Yastremska, who reached the semi-finals as a qualifier last year.

Former Wimbledon champion Rybakina was clearly hampered by a back problem for much of the contest on John Cain Arena.

“I knew I was not going to be able stay long in the rallies so I had to be aggressive,” she said.

“I’ll see my physio and he will do some magic.”