The Australian Open is now underway, with plenty of upsets having already taken place in Melbourne.

On the ATP Tour, 20th seed Flavio Cobolli lost in the first round to Arthur Fery, who emerged through qualifying.

American hopeful Sebastian Korda also lost his first match, as did seven-time Grand Slam champion Venus Williams on the WTA Tour.

Defending champion Jannik Sinner will soon take on Hugo Gaston, while Madison Keys begins her title defence against Oleksandra Oliynykova.

Rennae Stubbs doesn’t think Madison Keys can win the Australian Open

Keys’ chances of defending her title have now been discussed by former player Rennae Stubbs, who said on her podcast: “I don’t think she’s going to defend.

“And the reason I say that, it’s not because she’s not capable, she’s arguably the best hitter of the ball in women’s tennis.

“But she hasn’t had the same lead-up. She won Adelaide playing probably the best tennis of her life, came in here super confident.

“Whereas she’s had a lot of injuries, she’s had an iteration to her service motion again. So I just think that she just doesn’t quite have the same confidence she had last year.

“So I just don’t see her defending her title this year. I see Amanda [Anisimova] being the one who gets through there.”

Keys lifted the trophy in Adelaide before the 2025 Australian Open, where she claimed her maiden Grand Slam title.

At this year’s Adelaide International, the American beat Tereza Valentova before losing her quarterfinal to Victoria Mboko.

Naomi Osaka told she won’t compete for the Australian Open title

Another player Stubbs was tasked with discussing was Naomi Osaka, who like Keys is a former Australian Open champion.

She has, however, won the Grand Slam twice and is a four-time Grand Slam champion in total, while she is also a former world number one.

But Stubbs said of Osaka: “Look, I just think again, she just doesn’t have the tennis under her belt that she needs coming in here.

“Can she beat anyone on any given day? Absolutely. Naomi Osaka is a four-time champion of a major title.

“She knows how to win them. But everyone is so good now, and she has to get more tennis under her belt.

“I just don’t think she’s quite there enough to beat an Iga Swiatek or an [Elena] Rybakina or any of these players. But then again, who knows? We know she’s capable. She has the tools, that’s for sure.”

Osaka, who warmed up for the Australian Open by playing for Japan at the United Cup, meets Antonia Ruzic in round one in Melbourne.

READ MORE:Victoria Mboko gives her opinion on Madison Keys after beating her in Adelaide