Can anyone lay a glove on the men's best players, Jannik Sinner and Carlos Alcaraz? And how will the likes of Iga Swiatek, Coco Gauff and Elena Rybakina react to Aryna Sabalenka's surge in 2024?
Flashscore editors Finley Crebolder and Tolga Akdeniz give their predictions ahead of 2025.
Australian Open
Finley Crebolder: The 2025 season could start with a massive story if Novak Djokovic wins a 25th Grand Slam or Carlos Alcaraz becomes the youngest man ever to win a career Grand Slam, but I find it hard to see either of those things happening with Jannik Sinner on the scene.
He was insanely good on hard courts in 2024, only losing three times on the surface, and those losses all came a while ago now too with the world number one ending the year with 17 consecutive wins.
You can't fully rule Djokovic out given he's won the Australian Open 10 times and maybe bringing Andy Murray on board as a coach will be what he needs to get back to his best, but I just can't look past Sinner.
Things definitely aren't as clear-cut on the women's side but again I'm going with the favourite and predicting that Aryna Sabalenka will defend her title.
Iga Swiatek has never been great in Melbourne and Elena Rybakina is out of form, and while Coco Gauff and Qinwen Zheng could be big threats after enjoying strong ends to the season, I'm backing Sabalenka.
Tolga Akdeniz: It is impossible to bet against Sinner really. That hard court record is pretty formidable, and no one really came close to beating him at both the Australian Open and US Open last year, barring a freakishly good first two sets from Medvedev in the final in Melbourne.
Alcaraz is still hit or miss on occasion, and while I am curious to see Djokovic alongside Murray, it has to be Sinner for me
On the women's side, although I do really like the Goran Ivanesevic and Rybakina team, I think it might be a bit early in their relationship for her to win this slam. So I will go with Gauff. The momentum she was building at the end of last year was pretty remarkable, winning Beijing and the WTA Finals.
Prior to that period, she was looking pretty awful on the forehand wing and with her serve all year, but getting rid of Brad Gilbert and bringing in Matt Daly seems to have shored things up for her to an extent. She is clearly still vulnerable and not flawless, but she is generally more solid.
And if she can remain solid, her athleticism and ability to just return everything is a cheat code really, and at just 20 years old, she is surely just going to get better.
French Open
Finley Crebolder: One of the things I'm most curious about heading into 2025 is whether Sinner can master clay - he's only ever won one title on the surface - but even if he did, I'd still be backing Alcaraz to win the French Open for a second year in a row.
It's probably the Spaniard's best surface and definitely the one where he has the biggest advantage over his main rival. Djokovic and Alexander Zverev are good clay-court players who have caused him problems at Roland Garros in the past, but I think he'll beat anyone he faces.
I'm backing Swiatek to retain her title too and win the slam for the fourth year in a row, although I am less confident about it after Zheng beat her on Philippe Chatrier in the semi-finals at the Olympics.
For the first time in years, I'm not all but certain that Swiatek will prevail at Roland Garros given that match and the fact we don't how things are going to go with her and new coach Wim Fissette, but I'm not brave enough to bet her against her.
Tolga Akdeniz: I really don't want to just give Sinner and Alcaraz a share of the four Grand Slams, but it is really hard to see anyone else being able to upset the duopoly.
I think I am going to have to say Alcaraz here, unfortunately. A boring pick, but on the clay, how can anyone doubt him? I was tempted to say Zverev just to do something different as well as the fact that I have high expectations of him, but I backed him a lot in 2024, and he has lost my trust with all his inconsistencies.
Swiatek is probably the most obvious pick of the year at the French Open, but my thought process is a little different.
I really want to predict Zheng will win a Slam this year. Her progress has been fantastic over the last 12 months, and there is no doubt in my mind she will be a multiple Grand Slam champion at some point.
She beat Swiatek at the Olympics last year, and granted, the emotions and pressure are totally different when representing your country. But I think it adds a little intrigue to a French Open tournament that Swiatek has dominated, and I guess we don't really know what form she will be in at that point - although you can be pretty sure she will be firing at a scary level on the clay.
For the sake of just having a different pick and how big of a fan I am of her, I will go with Zheng, even if I'm not totally on board with it.
Wimbledon
Finley Crebolder: I've played it pretty safe with my picks so far, but for Wimbledon I'm going rogue - very rogue - and saying that the men's champion will be... Matteo Berrettini.
You probably think I'm crazy backing the world number 34, but he had a strong 2024 on the whole, boasting the fifth-highest win percentage of any male player, and looked back to his best by the end of it with him playing a huge part in Italy's Davis Cup triumph. When he's been at his best in the past, he's been a real force on grass, winning Queens in 2021 and 2022 and reaching the Wimbledon final in the former year.
The only players to beat him at Wimbledon since 2019 are Roger Federer, Djokovic, Alcaraz and Sinner, and he's in better shape now than when his compatriot narrowly beat him on Centre Court in the summer. Getting past Alcaraz would admittedly be tougher, but he gave the Spaniard a good game in 2023 when struggling to find form and fitness, so you never know.
The women's championship at Wimbledon has always been hard to predict in recent years with no top players consistently thriving on grass, but Rybakina has done so in the past and I think she will again.
The 2022 champion has had a year to forget due to various fitness issues but she remains the best grass-court women's player in the world when fully fit and has a new coach in Goran Ivanisevic who knows a thing or two about winning Wimbledon having done so as both a player and as Djokovic's coach.
Tolga Akdeniz: I am going with Sinner. I've got a really strong feeling for him at Wimbledon this upcoming season.
The Italian is a good grass-court player. He reached the Wimbledon semi-final in 2023 and lost to Djokovic, and only lost to Medvedev in the quarters in 2024 because he was injured. He is also the defending Halle champion.
If he is fit and firing, I think he may be able to get his hands on tennis' most coveted trophy.
On the women's side, I do really like the idea of Rybakina too. Her game has the tendency to be erratic, and coupled with health issues, she hasn't been able to make the impact at Grand Slams that her talent and ability suggest she should.
But she has been very consistent at Wimbledon, is a brilliant grass court player and is a former champion, and as mentioned previously, I think the tandem with Ivanesevic could be extremely good for her. I reckon she could be Wimbledon champion again.
US Open
Finley Crebolder: It was a real toss-up between Sinner and Alcaraz for me here but I've just about decided to go with the latter.
He beat Sinner in the best match they've ever played to date on his way to the US Open title in 2022 and there's also a chance that the Italian could be banned by this point in the year if the World Anti-Doping Agency are successful with their appeal - those two factors are enough for me to lean towards Alcaraz.
I didn't have an easy time deciding which woman to pick either but after considering Sabalenka, Rybakina and Gauff, I've ended up choosing Zheng.
With how quickly she seems to be developing, she'll be an even better player by the end of 2025 than she is now, and if that's the case, she'll be good enough to win her first Grand Slam title.
Tolga Akdeniz: The US Open is a really unpredictable Slam due to it being played towards the end of the calendar, but I repeat: can anyone beat Sinner on the hard courts - especially at the majors?
I genuinely don't see Medvedev or Zverev laying a glove on him, while Djokovic is not getting any younger or better. I am going to be boring and just say Sinner is going to win again and take home three majors in 2025. My apologies.
With the women, I am thinking I can't not give one of Sabalenka or Swiatek a Slam, and given Sabalenka's strength on hard court, she will surely reign supreme at either Melbourne or New York. So I will give this one to her.
Breakout players
Finley Crebolder: The young men's player I'm most excited about heading into 2025 is 21-year-old Frenchman Giovanni Mpethsi Perricard, who I can see really building on a solid season in which he won his first two ATP titles in Lyon and Basel.
Standing at 6'8 and possessing a monster of a serve, he could be a real threat to top players on his day and during the grass-court season in particular, and it's just nice to see a player with a good old one-handed backhand coming through.
The young talent on the women's side I'll be keeping an eye on most is Olga Danilovic, who ended 2024 by winning the second title of her career in Guangzhou.
She caught my eye in Roland Garros when she beat Danielle Collins and Donna Vekic as a qualifier and after a strong finish to the season, the 23-year-old could begin to fulfil her potential in 2025.
Tolga Akdeniz: There's a lot of hype around Joao Fonseca at the moment, especially after his Next Gen victory, but I can't say know too much about him currently. Who I do really like though, and someone I think has a massive future is Czech Jakub Mensik.
Just 19 years old, he's already got a strong, athletic build. He's a big server and hitter, but also got a lovely drop shot on him. He reached the Doha final in 2024 and beat Andrey Rublev in the semi-final, and also reached the third round at the US Open. I'm hoping he can be a more consistent force this season.
And a real outside pick and someone a lot of people probably don't know a lot about: 16-year-old Iva Jovic.
I hadn't heard anything about her prior to the US Open, but after being awarded a wildcard to play at Flushing Meadows, she became the youngest American to win a women's main-draw match there since 2000 when she beat Magda Linette. She then very narrowly lost out to Ekaterina Alexandrova in the second round.
She is one of the finest juniors in the world and does predominantly ply her trade on the ITA Women's tour, but she has been awarded a wildcard to play at the Australian Open. I'm not expecting her to become a real force of nature in 2025, but I am hoping she can really begin to showcase her talents to the world.