As Andy Murray walked out of a tennis court as a professional player for what could be the final time, the DJ at the Australian Open hit play on Joe Esposito’s ‘You’re The Best’.

You may know the song, especially if you’re over 30. Or younger and a cult classic aficionado.

It is the one used for the montage at the end of The Karate Kid, the classic 1984 film, just after the protagonist Daniel LaRusso defies logic, defies expectation and defies injury to beat his opponent.

By chance or by choice, it felt apt.

Unlike LaRusso, Murray did not claim an unlikely victory.

But, even in defeat against Spanish opponent Roberto Bautista Agut, it was another example of Murray defying the odds.

The Scot has done that throughout his career, taking the British public on a rollercoaster journey, on his way to Grand Slam titles, Olympic medals and leading his nation to Davis Cup glory.

Yet it was a surprise he managed to do it again in a four-hour thriller which left the 7,500 people inside the Melbourne Arena, and millions more back in Britain engrossed, excited and emotional.

Four days earlier, the 31-year-old broke down in front of the world’s media as he revealed he is set to retire this year because of a chronic hip injury which, even after surgery, has left him in pain putting on his socks.

Not only that, but also this tournament in Melbourne might even be his farewell.

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Pitted against 22nd seed Bautista Agut, and a few days after he struggled in a practice match against Novak Djokovic, most predicted a three-set – or, if you were more generous, four-set defeat against an opponent who recently won the Qatar Open title.

They were wrong.

Instead of going out looking like an imitation of the man who has entertained a nation, he went out looking almost like the man who gave British tennis some of its finest moments for the best part of a century.

“I know that I’m not the same player as what I was,” Murray said candidly afterwards.

Maybe not in terms of movement, but in terms of fighting spirit and never-say-die-attitude he certainly was.

And, largely, there was nothing wrong with his tennis skills: hitting some wonderful winners, landing serves of up to 130mph and doggedly defending his baseline like the old Murray.

With Murray believing this could be the end, it ensured there was one major story at Melbourne Park on Monday – and everyone wanted to see it.

That even meant compatriot Dan Evans, who had just won his opening match, was met by only one member of the British press as the rest trooped over to Melbourne Arena.

Murray’s match being put on the site’s third show court – instead of the bigger Rod Laver Arena or Margaret Court Arena – meant grounds pass holders could queue to bag a seat.

That ensured a partisan atmosphere which, at times, was almost akin to a Davis Cup tie.

Queues snaked from the concourse, down the stairs and out of the door long before the preceding match between Kyle Edmund – Murray’s successor as British number one – and Tomas Berdych came to an end.

In among the lines were plenty of familiar accents. And those who owned them were wearing Scotland football shirts, tartan skirts, Saltire flags, tammie hats…

Two particularly dedicated fans – Linda Tront and Bernadette Brown, originally from Paisley and Dundee but now living down under – even brought a meticulously crafted homemade banner.

Scottish blue and tartan tape carefully cut, sewn and stuck on a piece of silk, spelling out their personal message to their hero.

“There will only ever be one Andy Murray. Thanks for the memories,” it read.

It took about eight hours for Linda to make, she claimed. Staying up until the early hours to start crafting it and getting up not long afterwards to finish.

“We come here every year for Andy and have watched all of his five finals where he came runner-up,” Bernadette said.

“We have shouted with him, cried with him, we’ve done everything with him.”

Rarely is such dedication from a fan often matched by the subject of their affection. Murray is one of them and made sure he left everything he had out there on court – for himself and for his supporters.

“I didn’t care if I damaged my hip any more in the match,” he said afterwards.

“It was easier to deal with the pain knowing that I’m not going to play another match for at least five months or maybe not again.”

With the latter still a distinct possibility, despite seemingly refusing to rule anything out in his post-match news conference, this felt throughout like a farewell.

Mum Judy was sat in his player’s box, next to his older brother Jamie – who rarely watches his sibling, while the likes of Davis Cup captain Leon Smith and Fed Cup skipper Anne Keothavong, plus young British players Katie Swan and Harriet Dart, also lent their support.

Like those around them, Murray’s nearest and dearest constantly jumped to their feet, roaring encouragement and pumping their fists in his direction.

The first standing ovation came when Murray arrived on court – and countless more followed.

Moods and momentum swung. A positive start for the Briton, perhaps surprising many by being so competitive in the opening set, saw him earn a break point at 4-3 and that was greeted with a roar that Hampden would have been proud of.

But he could not convert and Bautista Agut – who you felt for being almost cast as the pantomime villain – seized his chance by breaking in the very next game.

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With regular renditions of ‘Let’s go Andy, let’s go!’ ringing in his ears, Murray missed more break points early in the second set as Bautista Agut again took advantage and took control.

The pain which Murray described on Friday was becoming clear by this point. His face becoming more contorted, his limp becoming more pronounced.

And the atmosphere, as a result, became more subdued.

That only became worse when Bautista Agut went a break up early in the third before, out of nowhere, Murray conjured up a break point.

A backhand winner did the trick as Murray – looking shattered physically and emotionally – slowly lifted his arms into the air in celebration.

Suddenly the belief was back as quickly in Murray and the stadium as it was draining from Bautista Agut.

The Spaniard famously coughed up a two-set lead to lose in five against another Brit, Cameron Norrie, in a Davis Cup match last February and any suggestion that it could happen again initially seemed a fanciful one.

Then Murray won the third-set tie-break – and then the fourth.

By this stage Murray had been walking back to the baseline after changeovers almost like a WWE wrestler staggering around the ring, geeing the baying crowd to get behind him even more with plenty of arm-waving and fist-pumping.

It was pandemonium.

Crackling PA systems, dodgy Hawkeye connections, fireworks from the nearby Melbourne Cricket Ground only added to the drama.

And then, in the blink of an eye, another twist sneaked up as Bautista Agut regained control and ran away with the final set.

Murray has often burst into tears at emotional moments in his career and threatened to do so again before he served to stay in the match at 5-1.

The whole stadium rose again to show their appreciation to one of the game’s greats, forcing him to pause and allowing him to thank them for their support.

“I was emotional at that moment. It was cool,” he said.

“I don’t think I’ve had that before in any matches.

“The atmosphere the whole match was amazing. I loved it. I’m really appreciative that the people gave me that atmosphere to play in.”

In the end, Murray could not finish with a final flurry like LaRusso. Yet a summer sequel in London – sure to be another blockbuster for the British public and a proper chance to say goodbye – is not out of the question.

John Isner became the first top-10 player to fall on the opening day of the Australian Open as he was stunned by world number 97 Reilly Opelka.

American Isner, seeded ninth in Melbourne, was beaten 7-6 (7-4) 7-6 (8-6) 6-7 (4-7) 7-6 (7-5) by compatriot Opelka in just over three hours.

The victory was Opelka’s first in the main draw of a Grand Slam.

Earlier, 17-time Grand Slam champion Rafael Nadal beat James Duckworth 6-4 6-3 7-5 to reach the second round.

Opelka – who at 6ft 11ins is the joint-tallest player on the ATP Tour – is the first American to beat 6ft 10ins Isner at a Slam.

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Spanish second seed Nadal, 32, saw off Australian Duckworth in two hours and 16 minutes on Rod Laver Arena, despite a stubborn finish from Duckworth.

“He was playing super aggressive, every shot,” Nadal said.

South African fifth seed Kevin Anderson also progressed by beating France’s Adrian Mannarino 6-3 5-7 6-2 6-1.

The 32-year-old, who has reached the fourth round at Melbourne Park on three occasions, served 14 aces but made 38 unforced errors as he won his opening match in two hours and 53 minutes.

The Wimbledon runner-up faces American Frances Tiafoe in the next round.

Nadal, who cut short his 2018 season with an abdominal muscle injury and to have ankle surgery, appeared to be back to full fitness against wildcard Duckworth.

The world number two showed no sign of being bothered by a thigh strain that had forced him to pull out of the Brisbane International earlier this month.

“I am trying to be better and better every day,” he said. “I had a good week of practice before this tournament.”

He will play either Australian Matthew Ebden or Germany’s Jan-Lennard Struff in the second round.