Germany’s Laura Siegemund was the talk of Melbourne Park on Wednesday as 32 second-round matches across both singles draws burst into life.

At 36 years old, the German world No.97 produced one of the shocks of the tournament so far to beat last year’s finalist and fifth seed Zheng Qinwen 7-6(3) 6-3.

That result is just the latest giant-killing act for the experienced right-hander, who counts Maria Sakkari, Simona Halep and Venus Williams among her list of victims over the years.

Siegemund wasn’t the only player to ruffle feathers on Day 4, as Czech teenager Jakob Mensik enjoyed one of his biggest wins yet to send sixth seed Casper Ruud packing, 2-6 6-3 6-1 6-4.

It was the fifth top-10 win of the fast-rising 19-year-old’s career just days after he beat Ben Shelton en route to the semifinals in Auckland last week.

Back to the women’s draw, and another seed went out when two-time former champion Naomi Osaka proved too strong for world No.20 Karolina Muchova 1-6 6-1 6-3.

The champion here in 2019 and 2021, Osaka’s victory puts her into the third round at a Grand Slam for the first time since giving birth in July 2023. The former world No.1 next faces Belinda Bencic, who is also back playing the sport after becoming a mum last April.

There were smoother passages for some of the other big names, with two-time defending champion Aryna Sabalenka extending her Melbourne Park win streak to 16 matches.

The 2023 and 2024 champion took out Spain’s Jessica Bouzas Maneiro 6-3 7-5 and will now prepare for a meeting with recent Auckland champion Clara Tauson in the third round on Friday.

Coco Gauff made it seven wins out of seven – and 14 sets out of 14 – so far in 2025, but had to recover from 5-3 down in the second before seeing off big-hitting Briton Jodie Burrage 6-3 7-5.

In-form seventh seed Jessica Pegula beat Belgium’s Elise Mertens 6-4 6-2 for the first time in her career, while it was a tougher day for 14th seed Mirra Andreeva, who needed a deciding tiebreak to get past Japan’s Moyuka Uchijima, only just edging the shootout 10-8.

Jack Draper is fast becoming the marathon man of the event after recovering from two sets to one and 5-3 down in the fourth set to beat Australian Thanasi Kokkinakis in a wild atmosphere at John Cain Arena.

The Aussie was broken to love when he served for the match in that fourth set, and Draper went on to clinch a hard-fought victory 6-3 in the fifth to make it back-to-back five-set wins this week.

There was better news for another Australian, world No.68 Aleksandar Vukic scoring a huge scalp against 22nd seed and last week’s Adelaide finalist Sebastian Korda 7-5 in the fifth set. That win puts Vukic into new territory, the first time the 28-year-old has reached the third round at a major.

The big three players in action on the men’s side – No.2 seed Alexander Zverev, third seed Carlos Alcaraz and 10-time champ Novak Djokovic – all went through, although for the second successive match Djokovic needed four sets.

The Serb, who hopes to win a record-breaking 25th major in Melbourne, recovered from losing the second set to eventually see off Portuguese qualifier Jaime Faria 6-1 6-7(4) 6-3 6-2.

Djokovic will play dangerous Czech Tomas Machac, who beat Reilly Opelka in five sets. Machac beat Djokovic on clay in Geneva last year.

Alcaraz hammered his way past Japan’s Yoshihito Nishioka for the loss of just five games, while Zverev cruised through against Spain’s Pedro Martinez 6-1 6-4 6-1 during the Rod Laver Arena night session.

Night turned to day for Spain’s Alejandro Davidovich Fokina and Felix Auger-Aliassime, the 29th-seeded Canadian and AO 2022 quarterfinalist letting a two-set lead slip to go down 6-7(7) 6-7(5) 6-4 6-1 6-3 in a match that finished at 1.11am on Thursday.