Djokovic, Murray and Williams return as Nadal and Federer aim for more of the same: What to expect in the 2018 tennis season

What are you expecting from Novak Djokovic in 2018? Jon Turner: Domination. Rested, recuperated and refocused, the Serbian has plenty to play for and hardly any ranking points to defend in the second half of the season. Rafa Nadal and Roger Federer both limped through the end of 2017, and it remains those two who represent Djokovic's chief rivals. As impressive as Nadal and Federer were in 2017, a top form Djokovic is still the best player in the world. Watch him prove it in 2018 with at least one grand slam title and a return to the No 1 ranking. Graham Caygill: If he can recapture the drive and motivation that he had up to June 2016 then expect at least two majors to come his way and for him to end the year as world No 1. The past six months out could prove to be a blessing in disguise in terms of giving him time to rejuvenate. Chitrabhanu Kadalayil: Significant improvement from 2017. After struggling with form and injury, the Serb was right to call an early end to the season. He will have found the comebacks of Nadal and Federer instructive and will likely choose carefully what tournaments to play. It is doubtful whether he will win a record seventh Australian Open title, although there is a temptation to predict he will. But he will win at least one major in 2018. Will Nadal and Federer continue to dominate? Jon Turner: After boldly exclaiming Djokovic will rule the tennis roost this season, that should answer the question. Nadal, injury-permitting, will still be the king of the clay swing and Federer will still be the most feared man on grass, but expect both to face bigger challenges from other rivals - none more so than Djokovic - in 2018. Graham Caygill: No. I think Nadal will struggle to maintain his form of 2017 and would be smart to focus his efforts on the clay season. Federer's body appeared unable, or unwilling, to maintain high levels of competition for a sustained period of time. Nadal will be favourite for the French Open, and Federer for Wimbledon, but it would be a surprise if either wins the Australian Open or the US Open. Chitrabhanu Kadalayil: Nadal will still be the top contender to win the French Open, while Federer has to fancy another shot at Wimbledon. But they will not divvy up the major spoils between them like they did in 2017. Djokovic, Andy Murray and Stan Wawrinka will return to competitive action, making it hard for one or two narratives to dominate 2018. Expect an open season. Has Andy Murray fallen behind the leading pack? Jon Turner: There is a fear that the British No 1 has had his time in the sun when he rose to world No 1 in 2016. His form in 2017 was patchy at best and produced just one title. But it is clear that the hip injury that forced him to cut his season short had been a bigger and more long-term problem than was initially thought. Fully recover from that, and he'll be right in the mix next year. Graham Caygill: The big question is if he is fit at all, given the reports of his hip still bothering him. It may well have been that 2016 was as good as it was ever going to get for the three-time major winner. If he can get fit it will take time for him to get up to speed. It will be a shock if he wins a grand slam title in 2018. He will be the best of the rest behind the elite group of Djokovic, Federer and Nadal. Chitrabhanu Kadalayil: There is plenty of uncertainty around Murray's comeback. He will reportedly not be ready to play at the Brisbane International, which is a key warm-up event for the Australian Open. He will likely struggle in the early tournaments after, including Dubai where he won in 2017. His best chance to win another major remains at Wimbledon or Flushing Meadows. He should prepare keeping the second half of the season in mind. If he tries to rush his comeback, he will likely struggle to return to the top of the rankings. There is hope yet, but it is a 50-50 scenario. Will we see a first-time grand slam champion in 2018? Jon Turner: No. Much could depend on the fitness of the 'Big Five'. If Nadal is missing for the French Open then Dominic Thiem will fancy his chances as the second-best clay court player in the world. Grigor Dimitrov has the talent on grass and hard courts and will look to kick on from his triumph at the ATP Finals, while Alexander Zverev will continue his march towards world-class status. Then there are guys like Nick Kyrgios, David Goffin, Milos Raonic, Kei Nishikori, and Marin Cilic. But ultimately, no - the four majors will be shared by the usual suspects. Graham Caygill: Yes. The French Open could be wide open if Nadal's level drops, and Thiem will be a serious contender. The US Open is often a case of last man standing given the demands of the tour, and players such as Zverev should really target trying to peak at that time of year, rather than at an ATP 500 or ATP 1000 event. Thiem at the French and Zverev at the US Open are both realistic scenarios. Chitrabhanu Kadalayil: Yes. The most frustrating thing about 2017 was the inability of an emerging player to challenge the usual suspects at grand slam tournaments. Given the way the season panned out, however, there is a good chance one of Dimitrov, Thiem or Zverev will win in 2018. And if there is one major where there is likely to be a first-time winner, it is the Australian Open. With fitness being a concern for some of the top players, one of Dimitrov or Zverev will go on and win. Who is your ATP player to watch for this season? Jon Turner: Andrey Rublev. The 20-year-old Russian enjoyed a breakthrough season in 2017, rising from No 156 in the world rankings at the start of the year to end at No 39, winning his first ATP Tour title at the Croatian Open. He hits the ball like a cannon and possesses an unreliable temperament - the exact attributes for an entertaining player! Graham Caygill: Diego Schwartzman. The Argentine has been around a while but showed real signs of breaking through last year. Now up to No 26, he has the ability, especially on clay, to kick on and make a name for himself in 2018. Chitrabhanu Kadalayil: Denis Shapovalov. Beating Nadal at the Rogers Cup has got to be one of the great upsets of 2017. The win endeared him to plenty of fans around the world, not just because he beat a great player, but also for what had happened earlier in the year when he inadvertently injured a chair umpire and got suspended. Just 18 years old, the Canadian was named Most Improved Player and Star of Tomorrow at the ATP World Tour Awards. He has an aggressive game built around a solid forehand. He has an easy-going attitude, which could work for him while the stakes are high. But there is a risk he could end up becoming more like Jo-Wilfried Tsonga. How do you see Serena Williams' comeback going? Jon Turner: It will depend on how she wants it to go. If Williams wants to come back to the tour full-time and dedicate her life to tennis again then no question, she returns to be the dominant force of the WTA Tour. More likely, she will cut back on her schedule as she balances life as an athlete and mother. Either way, she will be the favourite for every tournament she does play in. Graham Caygill: Given no-one has capitalised on her absence to dominate, it would be a shock if Williams does not win at least one major title this year. She is the unpredictable element of the WTA Tour as even she will not know what impact motherhood has had on her. Unlikely to do a schedule that allows her to get back to No 1, she should still be at least top five by the close of 2018. Chitrabhanu Kadalayil: Serena Williams might fancy her chances to win at least three more grand slam titles to cross Margaret Court's record tally before she retires. But having embraced family life this year, she will likely pick and choose what majors to play, so winning three in one year looks next to impossible. Given the lack of a dominant star in women's tennis, she will be remain a top contender at any tournament she plays in. She will be more susceptible to bad days on court, however, and there is a host of big-hitting opponents who are capable of upstaging her at the business end of a competition. She will probably win one major in 2018. Will one player establish herself as the WTA Tour No 1? If so, who? Jon Turner: No, it will be another season of chopping and changing. There are too many players on a similar level for one to break out and claim the throne for a prolonged period of time, particularly if Serena Williams has a selective season. If there was going to be one, it would be Garbine Muguruza, but she - like all of her rivals at the top - struggles for consistency. Graham Caygill: You feel that if Simona Halep can just win one major it might lead to the Romanian winning three or four. Confidence is her problem. She deserves to be No 1 at present and if she can start 2018 well she should be able to stay there for the bulk of the year. Chitrabhanu Kadalayil: Yes, it will be Garbine Muguruza's year to finally establish herself as the undisputed No 1. Consistency is a problem, but she has improved year on year. Her ambition and fighting spirit were on show at the French Open and, even though she did not defend her title, she was at another level at Wimbledon. She was disappointing on the hard courts thereafter, but she will learn from the experience to come back stronger in the first half of 2018. What can we expect of Maria Sharapova? Jon Turner: A rise to top 10 in the rankings and a grand slam final. Sharapova belongs in the upper reaches of the WTA Tour and should push on this season. Don't be surprised if she goes all the way and wins one of the majors, too. Graham Caygill: Much hype with little in the way of results.Returned from her ban to much fanfare and though she beat Halep at the US Open, the fact she did not go on and win it was telling. There probably is a sixth major in her, but with Williams back and the competition at the top of the draw, a run to the last four at a major is probably as good as it gets. Chitrabhanu Kadalayil: She is determined to make up for lost time following her suspension, and she is still good enough to reach the semi-finals or final of a major. But with so many contenders in the women's game, it is next to impossible for her to win a major in 2018. She will continue to attract public and media attention, but her season will be more steady than spectacular. Who is your WTA player to watch this season? Jon Turner: Sloane Stephens. The American produced the most impressive two weeks of the season when she stormed to the US Open title. Her record after Flushing Meadows though? Six matches, six defeats. Stephens, who missed a year of action with a foot injury, has the talent to be a top five player and consistent contender in the major tournaments. It will be interesting to see how her 2018 season plays out. Graham Caygill: Caroline Garcia. The French player had an impressive, if understated 2017, getting to at least the last 32 at every major and being a quarter-finalist at the French Open. It could well be another unpredictable year of women's tennis ahead and the 24 year old has the consistency to do even better in 2018 and move up higher than No 8 in the world. Chitrabhanu Kadalayil: If Garbine Muguruza needs to fear one player to rival her over the next few years, that would be Jelena Ostapenko. The Latvian has the potential to rewrite the playbook. Opponents will struggle to find a strategy to counter her ability to hit winners on a consistent basis and her predisposition to keep games short. She has already won a major, at the French Open last year, but she will get even better in 2018.

Djokovic, Murray and Williams return as Nadal and Federer aim for more of the same: What to expect in the 2018 tennis season

As the ATP and WTA Tours enter 2018, The National's sports desk offer their thoughts on the big questions dominating the start of the season.