ANDY Murray’s seemingly bottomless reservoir of grit and determination feels like both a blessing and a curse at this stage of his career. The greatest Scottish athlete of all-time – and surely even Chris Hoy and Kenny Dalglish would concede that one – is facing up once more to his sporting mortality ahead of his planned participation in this month’s Australian Open.

Murray, a five-times runner-up in Melbourne, won’t be among the favourites or even seeded this time around. A lengthy and laborious rehabilitation from hip surgery this time last year has seen to that. His evident anguish and emotion as he spoke about that gruelling process following his recent first-round victory in Brisbane revealed the depth of his struggle.

It had been “a really hard 18 months” but he was happy simply being back on a tennis court. Tellingly, he also admitted that he “didn’t know how much longer it’s going to last”. In the short-term, the answer was the following round in Brisbane where he was beaten by Daniil Medvedev. But it was perhaps also a first real indication that a career that has already exceeded expectation by some distance – three Grand Slam titles, eight other major final appearances and two Olympic golds – might be gradually winding to a close.

Others would likely have already called it a day by now, but few can match the 31 year-old when it comes to resolve, tenacity and perseverance. Dr John O’Donnell, the Australian surgeon who operated on his hip, revealed that it was only Murray’s “intense desire to do well that has kept him going as long as he has” and that it was not a surprise that the Scot was still not feeling 100 percent after such a long road to recovery. “He’s been walking a tightrope for some time,” he added.

How long Murray decides to stay on that tightrope remains to be seen. He will listen to the aches of his body as well as to the advice of his medical team, but the man from Dunblane would likely not have undergone such a gruelling recovery programme if he didn’t believe he could emerge from it as a serious contender for the major prizes once more.

Such is his indomitable spirit and will to win, it is difficult to imagine him continuing to play through the pain if it becomes apparent he can no longer compete among the elite. Every athlete has to cope with the relentless marching of time and the increasing frailty of their bodies, and all deal with it differently.

Some choose to preserve their legacy by going out at the top, while others plump for longevity and continue to plough on among lesser lights. The notion of Murray, currently 240th in the world, being sustained by the occasional tour victory seems at odds with his “be the best” mindset. He has won Wimbledon (twice) and the US Open, reached the finals of the other two Grand Slams. There has been Olympic and Davis Cup success, too. He has nothing left to prove and it remains to be seen whether simply a love of the game will be enough for him to carry on.

What can be said with greater certainty is that he will only bow out when he alone feels the time is right. The spotlight will intensify should his Australian Open appearance be a brief one, or if the injuries return. Former players and pundits will suggest it is time for him to quit. Murray, you can be fairly certain, won’t listen to any of them. This will be his call and he won’t rush into it.

Murray may also take some strength from the renaissance of his major rivals following difficult times in their own careers. Roger Federer was similarly written off at the end of 2016 when the then 35-year old endured a campaign blighted by a knee injury. The Swiss failed to win a title for the first time in 16 years and also dropped out of the world top 10, having not won a grand slam for four years. A year later, however, and he was Australian Open and Wimbledon champion once again.

Rafael Nadal has also struggled with his fitness, most notably a recurring knee injury that may yet keep him out of the Australian Open. His struggles in 2015 and 2016, in particular, where he failed to claim a major title for the first time in a decade, had some commentators wondering whether the Spaniard was on the wane. His response was to bounce back with three major titles and regain his spot as the world number one.

Novak Djokovic was troubled with an elbow injury in 2017 that eventually needed surgery but he returned to win Wimbledon and the US Open titles last year and is once again the ranked as the best player in the world. The Serb, less it be forgotten, is only a week younger than Murray, while Nadal at 32 and Federer at 37 are both older. Age alone shouldn’t be a barrier to the Scot continuing as a force at the highest level.

This has been a remarkable era for men’s singles tennis but it must come to an end eventually. Murray won’t want to be the first of that group to retire and the stubborn streak that runs right through him will ensure he won’t give up without a fight. We are guaranteed that if nothing else.