Volkswacht Bodensee - Sinner surges into Melbourne last 16 on 'great day' for happy couple

Also into the second week is 38-year-old Gael Monfils after he stunned fourth seed Taylor Fritz -- with the veteran's wife Elina Svitolina also enjoying a shock win immediately after on the same court.

"It's really a great day for us today, beating top-four players and playing great tennis," said Ukraine's Svitolina.

American qualifier Learner Tien, 19, won in straight sets to extend his fairytale run on his debut in Melbourne.

But Danielle Collins, the pantomime villain after thanking hecklers for "paying my bills" in the previous round, lost and was booed.

Italian world number one Sinner dropped a set for the first time in 14 matches in the second round.

But there were no such wobble against the unseeded Marcos Giron on Rod Laver Arena as he sprinted home 6-3, 6-4, 6-2 in 2hr 1min, slamming 35 winners and eight aces.

Awaiting him next is either Serbian Miomir Kecmanovic or Danish 13th seed Holger Rune.

"If I want to go on in this tournament I have to improve," said the 23-year-old Sinner.

French showman Monfils rolled back the years to storm back and defeat the American Fritz 3-6, 7-5, 7-6 (7/1), 6-4.

The unseeded Monfils, who hit a career-high ranking of six in 2016 but is now 41st, is enjoying a late-career flourish.

A week ago he became the oldest singles champion in ATP Tour history when he swept to victory at the Auckland Classic.

Monfils faces another American in 21st seed Ben Shelton, who is a big fan.

"I think that any time he's on the court, it's a box-office match," said Shelton.

Monfils is married to Svitolina, who emulated his giant-killing efforts when she defeated world number four Jasmine Paolini, also on Margaret Court Arena. Svitolina came though 2-6, 6-4, 6-0.

"I warmed up the court for her," joked Monfils.

Tien became the youngest man to reach the fourth round since Rafael Nadal in 2005 when he overcame injured Frenchman Corentin Moutet.

The gifted teenager won 7-6 (12/10), 6-3, 6-3 with Moutet collapsing clutching his leg in the third set before gamely carrying on.

"Honestly it feels pretty crazy to be in the second week," he said.

Tien stunned three-time runner-up Daniil Medvedev in a five-set epic in the previous round.

Home hope Alex de Minaur, the eighth seed, went through in four sets against Argentina's Francisco Cerundolo and will face American Alex Michelsen for a place in the quarter-finals.

- Rampant Swiatek -

In a one-sided battle of former US Open champions, Swiatek romped to a 6-1, 6-0 triumph in a statement victory over Raducanu as she pursues a first Melbourne crown.

Emma Navarro, the eighth seed from the United States, joined the Pole in the next round with a gritty three-set win over Ons Jabeur.

Sixth seed Elena Rybakina also advanced despite a back problem.

"I felt like the ball is listening to me," Swiatek said after rattling off 11 straight games in a brutal display against Britain's Raducanu on Rod Laver Arena.

The 23-year-old Swiatek is a five-time major winner but she has never gone beyond the semi-finals at Melbourne Park.

She faces world number 128 German Eva Lys next.

Lys beat Jaqueline Cristian of Romania in three sets to become the first women's singles "lucky loser" to reach the fourth round since the event moved to Melbourne Park in 1988.

Former Wimbledon champion Rybakina of Kazakhstan needed a medical timeout to treat a back spasm before winning 6-3, 6-4 against Dayana Yastremska of Ukraine.

Asked if her back would be OK, she replied: "Not really. So I will see my physio and hopefully he does some magic."

Rybakina will face Madison Keys after she swatted aside fellow American Collins 6-4, 6-4, with Collins getting booed in and out of the arena.

Novak Djokovic, Carlos Alcaraz, Aryna Sabalenka and Coco Gauff are all in action on Sunday.

L.Meier--VB