Tsitsipas destined for Slam glory after ATP Finals triumph, Nadal and Barty's magic seasons

As Stefanos Tsitsipas bumbled his way through his speech under the O2 lights, it was clear he wasn’t used to winning. But on the basis of his victory in London, he’s going to get plenty of rehearsal time over the coming years.

The same question is always asked of the new generation: have they got the mental fortitude to back up their talent? So far, the answer has been no. Alexander Zverev is the obvious example – a player who has looked so comfortable in three-set matches but seems burdened by the ‘future world number one’ tag attached to him when ever the Slams come around.

Perhaps Tsitsipas will be different. Not only was he brilliant on both wings during his tremendous week at the ATP Finals – firing down winners with a whipping forehand and throwback one-handed backhand – but he also has the mental strength which offers the greatest hint of a bright future. The Greek resisted 11 of 12 break points against Roger Federer in the semi-finals before staying composed in the decisive tie-break against Dominic Thiem, despite having almost no major final experience and all aged just 21. On this evidence, a Slam title is on the horizon.

Dominic Thiem fell short yet again in a final of a top event, and it could so easily have been different. After battling ferociously to win the opening set at the O2 Arena, he appeared to have Tsitsipas where he wanted him, yet he faded horribly - and very unexpectedly - in the second set and was never able to quite regain his edge.

He looked utterly dejected in his chair after the ATP showpiece, and perhaps he was ruing what might have been in a year when he also lost another Grand Slam final. But it was not just another spirit-crushing defeat in a top final: losing to a player five years his junior after having held the ascendancy made it all the more chastening.

Thiem's achievements this season should not be ignored: reaching the finals of Roland Garros and the ATP Finals was a fine effort and losing to Rafael Nadal on the red clay is never going to haunt a player too much. Yet the 26-year-old finds himself in a tough spot having been the 'nearly man' for a few years now and with an abundance of talent coming through. Losing to one such younger talent in good friend Tsitsipas in London may prove particularly hard to digest for Thiem given the opportunity that presented itself after the opening set on Sunday night.

Andy Murray is the great unknown. In under a year, he was retired at the Australian Open (despite never saying so), had surgery that would likely end his playing career (he returned five months later) and looked destined to drift into obscurity as a doubles player (he beat Stan Wawrinka to win the European Open singles title in October). Right now, making any predictions about him is pointless.

And yet, although an extended run at a Grand Slam looks difficult – best-of-five quickly exposes physical faults – it’s not inconceivable that he could climb the ATP charts enough to return to London among the world’s top eight players. With the Finals moving to Turin from 2021, what better send-off than Murray writing another chapter in his miraculous comeback at the farewell tournament?

Nadal usurped Novak Djokovic to snatch back top spot in the ATP rankings for the eighth time in his illustrious career at the start of November, and it capped what has been another sensational year for the Spaniard with so many still expecting to see his dominance fade.

The 33-year-old won four titles in total this season: a ninth Rome Masters crown; a 35th ATP Masters 1000 trophy at the Montreal Masters; his 12th Roland Garros triumph; plus a fourth US Open to round off the Slams in style. Holding off Djokovic for the season-ending world number one spot further cemented what a strong campaign he has enjoyed.

Daniil Medvedev gave him a real scare in the US Open final and demonstrated his serious talent, but ultimately Nadal still had enough to pull through when it really mattered - as he also did at Roland Garros in keeping Thiem at bay yet again - and two Grand Slams for the season has shown he remains as tough to beat as ever.

What a season it has been for Ash Barty. The Australian was utterly dominant in claiming her maiden Grand Slam title at Roland Garros with a straight-sets win over Marketa Vondrousova, and her triumph at the £3.4m WTA Finals rounded off a stunning year pretty perfectly.

The 23-year-old became the first Australian to top the WTA rankings at the end of the year since they were introduced in 1975 and capped a stellar season in Shenzhen as she followed in 1976 WTA Finals champion Evonne Goolagong Cawley's footsteps.

Barty could well go from strength to strength in 2020 given her durability and the way her game has developed so effectively. She always gets incredible support at Melbourne Park and this could be the year she gives the home fans what they so crave at the Australian Open.

If Serena Williams plans on usurping Margaret Court in the all-time Grand Slam charts, she will need to get a move on. The women’s game is on the cusp of a changing of the guard as a host of exciting teenagers compete to replace the established names.

Bianca Andreescu and Coco Gauff are the standout talents after respective runs to the US Open crown and a first WTA title aged 15. If Andreescu can keep the injuries away, she will quickly add to her major haul, while Gauff has ominously been dubbed the ‘new Serena’. But there’s more. French Open semi-finalist Amanda Anisimova (18), three-time WTA title winner Dayana Yastremska (19) and 2019 breakout act Iga Swiatek (18) will all be aiming to drive deep into Slams in 2020.

The upshot? Probably best you go all out in Melbourne, Serena…