The Australian Open starts on Sunday when Jannik Sinner and Aryna Sabalenka will be defending their respective men’s and women’s singles titles.

World No 1 Sinner also won the US Open last year and betting sites make him the 2.5 favourite for a successful title defence in Melbourne.

Sabalenka, the highest-ranked player in the women’s game, won the same two majors last year and is 3.25 to win the Australian Open for a third successive year.

In the men’s tournament, four-time grand slam winner Carlos Alcaraz is available at 4.5 for a first success Down Under.

Novak Djokovic, looking to win this tournament for an 11th time and extend his grand slam record to 25, is a best-priced 5.5 with Ladbrokes.

Coco Gauff, a semi-finalist two years ago, is regarded as Sabalenka’s nearest rival at 5.0, closely followed by former world No 1 Iga Swiatek (6.0), who has only once progressed beyond the last eight in six attempts.

All of these players have a great chance of lifting their respective trophies on the weekend of January 25-26, but what about the dark horses for the year’s first grand slam?

Gambling.com takes a look at some of the Australian Open outsiders that could spring a shock in the men’s and women’s singles.

Men’s Australian Open Outsiders: Alexander Zverev

The German has been knocking on the door for several years only to fall short, but could 2025 finally see him fulfil his ambition by getting his hands on a major trophy?

Zverev is second in the world rankings and last year reached the semi-finals for the second time by defeating Alcaraz only to squander a two sets to love lead against Daniil Medvedev in the last four.

In the previous five years, the 2020 Olympic champion has reached the last four of a grand slam on six occasions and the finals twice, so his pedigree cannot be questioned.

Zverev has a superior record against both Sinner and Alcaraz in the head-to-heads, so it would be wrong to dismiss his Australian Open prospects at 12.0 with Ladbrokes.

Men’s Australian Open Odds: Alexander Zverev – 12.0 With Ladbrokes

Men’s Australian Open Outsiders: Taylor Fritz

Fritz had the best season of his career in 2024 when he reached the last eight at the Australian Open and Wimbledon before losing to Sinner in the US Open final.

Two titles at Eastbourne and Delray Beach, plus an appearance in the championship match at the ATP Finals, helped him rise to a career-high fourth in the world rankings.

Fritz has lost his last four duels with Sinner, so he may need some help from the draw, but he is an eye-catching 29.0 with betting apps for Australian Open glory.

Men’s Australian Open Odds: Taylor Fritz – 29.0 With Bet365

Men’s Australian Open Outsiders: Matteo Berrettini

Big-serving Berrettini missed last year’s Australian Open with a foot injury which meant he also had to withdraw from the French Open for a third successive year, but otherwise it was a decent season for the Italian.

After an injury-ravaged 2023, Berrettini won three titles in 2024, all surprisingly on clay – the slowest surface. 

An Australian Open semi-finalist in 2022, Berrettini is a dangerous floater as a non-seed, one that elite players will be keen to avoid.

Berrettini is available at 151.0 with Unibet in the Australian Open odds.

Men’s Australian Open Odds: Matteo Berrettini – 151.0 With Unibet

Men’s Australian Open Outsiders: Andrey Rublev

Rublev regularly makes it to the quarter-finals of grand slams, but has never gone further.

Since the 2017 US Open, the Russian has made it to the last eight in 10 of his 24 major appearances which is a remarkable record.

The world No 9 is 81.0 with Ladbrokes to finally break his duck, but there’s no reason to think he has the weapons to beat the likes of Sinner, who beat him in straight sets in last year’s Australian Open quarter-final.

The draw will be made on Thursday, so it’s worth checking the odds on Rublev reaching the last eight in Melbourne for the fourth time in five years.

Men’s Australian Open Odds: Andrey Rublev To Reach QF – TBD

Women’s Australian Open Outsiders: Zheng Qinwen

Zheng had a breakout season in 2024 during which she reached the Australian Open final, won the Gold Medal at the Paris Olympic and two other titles.

A run to the championship match at the WTA Finals, which she lost in a final-set tie-break to Gauff, saw her reach a career-high fifth in the world rankings.

Zheng lost three times to Sabalenka last year, twice in grand slams, so the 22-year-old Chinese will have to raise her game should their paths cross in the latter stages of the tournament.

Having reached the US Open quarter-finals for the second successive year, the scene is set for another big year for Zheng, who is 15.0 with Bet365 for a maiden major.

Women’s Australian Open Odds: Zheng Qinwen – 15.0 With Bet365

Women’s Australian Open Outsiders: Jasmine Paolini

Paolini, like Zheng, had a stunning 2024 during which she reached two grand slam finals at Roland Garros and Wimbledon.

The diminutive Italian also won the biggest tournament of her career in February, the Dubai Duty Free Championship – a WTA 1000 event.

Despite being at a career-best fourth in the WTA rankings, Paolini is 41.0 with the best tennis betting sites to win the Australian Open where last year she ended a run of four successive first-round exits by reaching the last 16.

Her hard-hitting groundstrokes and all-round energetic game should suit her well, but on the negative side Paolini has never beaten Swiatek or Gauff in five combined attempts, and trails 3-2 in the head-to-head with Sabalenka.

Women’s Australian Open Odds: Jasmine Paolini – 41.0 With Unibet

Women’s Australian Open Outsiders: Mirra Andreeva

At 17, Andreeva has time on her side to win plenty of grand slams but could she spring a surprise over the next fortnight?

The Russian thrashed sixth seed Ons Jabeur on her Australian Open debut last year for the loss of just two games and in the fourth round took the opening set against Barbora Krejcikova, who went on to win Wimbledon, only to fade.

Her preference for clay saw her beat Sabalenka en route to the semi-finals of the French Open and she also won her first WTA title on that surface in Iasi, Romania.

But she has made a decent start to the new hardcourt season, reaching the semi-finals in Brisbane where she lost to Sabalenka, and looks a livewire at 26.0 in the Australian Open odds.

Women’s Australian Open Odds: Mirra Andreeva – 26.0 With Ladbrokes