MELBOURNE — Sixth seed Ons Jabeur and former champion Caroline Wozniacki both fell victim to exciting young Russians in the Australian Open second round on Wednesday.

The veteran pair were no match for Mirra Andreeva and Maria Timofeeva, who emphatically stamped their mark on the opening Grand Slam of the year, which was marred by rain on day four.

Fourth seeds Coco Gauff and Jannik Sinner, along with local hopeful Alex de Minaur and world No 11 Barbora Krejcikova, however, had no trouble progressing.

Andreeva, just 16, was in scintillating form to take down 29-year-old three-time major runner-up Jabeur 6-0, 6-2 in less than an hour under the closed roof of Rod Laver Arena.

"It was probably the best match (ever)," said Andreeva, a schoolgirl who burst onto the scene when she reached the fourth round at Wimbledon last year as a qualifier.

"Yes, I was preparing for this match, and I knew what she was going to do," Andreeva said. "I'm also not bad at dropshots, (but) I decided not to attempt a lot of those, because I think that she's better.

"It was just the momentum when I decided to do so. I think she's still better than me at this, but I will improve!

"The first set, I didn't expect that I would play this well. The second set was also not bad. So, yes, for me it was an amazing match."

Her reward is a third-round clash with France's Diane Parry.

In a later news conference, she summed up her progress to date: "I don't think that I achieved something incredible. I still have time to do that."

Timofeeva, a 20-year-old qualifier, was equally impressive against 2018 champion Wozniacki, who flew through the first set and was a break up in the second.

Undeterred, Timofeeva, showing impressive power, hauled herself back into the contest and ultimately prevailed against a player 13 years her senior, winning 1-6, 6-4, 6-1.

"It was an honor to play here against Caroline today. I'm just beyond happy and couldn't ask for more," she said after setting up a testing third-round meeting with 10th seed Beatriz Haddad Maia.

Sinner, the driving force behind Italy's first Davis Cup triumph, was delighted that the inclement weather forced the roof of Margaret Court Arena to be closed for his match against Jesper de Jong.

The fourth seed, who skipped all the warm-up tournaments this year, hit a rich vein of form at the end of last season on indoor courts and simply dominated the Dutch qualifier 6-2, 6-2, 6-2.

"Roof closed, it's a little bit different. I love the conditions," Sinner said. "But it's part of a tournament that, when it's raining, you can try to adapt yourself to different situations."

The rain finally relented and the roof was back open for US Open champion Coco Gauff's second-round clash with fellow American Caroline Dolehide.

It initially looked like the women's fourth seed would follow Sinner's lead, but Dolehide dragged her into a real scrap and Gauff was forced to fight until her fourth match point to prevail 7-6 (2), 6-2.

"It was really hard, I started off playing well, but she does well hitting the ball heavily, so it's tough to be on the offensive," said Gauff.

"I wasn't nervous today, I was just trying to play good tennis."

The 19-year-old will now play another compatriot, Alycia Parks, who beat former US Open finalist Leylah Fernandez 7-5, 6-4.

Agencies