Credit: X / Eurosport / Australian Open

As Novak Djokovic produced a performance up there with the best of his wins over former rivals Roger Federer and Rafael Nadal, he turned to Sir Andy Murray in celebration.

Letting out his second guttural roar, he walked over to his courtside box and hugged the newest member of his coaching staff; his former rival-turned coach.

Djokovic’s strategy was near-perfect against Carlos Alcaraz in the Australian Open quarter-finals. Some of the rallies were made for the highlight reel and left both players out of breath as a 37-year-old Djokovic looked every bit the player he had been a few years previously.

The gap of 15 years 349 days between Djokovic and Alcaraz is the biggest in a grand-slam quarter-final since Jimmy Connors vs Andre Agassi at the US Open in 1989.

Djokovic’s record at the Australian Open stands at 99 wins to just nine losses, as he remains in the hunt for a record-extending 11th men’s singles title at Melbourne Park.

Here, Telegraph Sport looks at the key moments where Murray’s impact was most keenly felt by Djokovic during his four-set epic.

Murray’s calm head as Djokovic loses super point

In the fourth set, with Djokovic on break point, he and Alcaraz were involved in a thrilling baseline rally. The Serb and Spaniard were grunting with exertion, before the youngster claimed the point after 33 exchanges.

Djokovic then turned to his bench and gestured in anger, only for Murray to stand there stoic, only slightly tugging at his ear and providing the perfect calm setting to contrast the on-court anger.

It suggests that behind the scenes Murray provides the calm, rational antidote to Djokovic’s more emotional personality.

The embrace between the pair

After sealing his place in the semi-finals, Djokovic immediately walked over to his box, both fists clenched and pumped, yelling in celebration.

Again, Murray was more of a figure of calm, clapping, before mirroring Djokovic’s double fist pump, with the pair then hugging.

While it will take a while for tennis fans to become accustomed to Murray sitting in the box of his long-time rival, it is clear that Djokovic values his input, thanking him before any other member sat courtside in the immediate aftermath of his victory.

The sigh of relief

When Djokovic won the fourth and decisive set just before 1am local time after a match lasting three hours and 38 minutes, the camera almost immediately panned to Murray next to the court, who breathed a long sigh of relief. Murray’s first venture into the realm of coaching will continue with a semi-final meeting with Alexander Zverev, who knocked out British tennis player Jacob Fearnley.

Credit: X / Eurosport / The Australian Open

Consoling Alcaraz

After the match, while Alcaraz was cooling down on one of the bikes in the area available to players, Murray made a point of walking over and congratulating the young Spaniard. Alcaraz was left smiling as the pair exchanged a brief word or two, before Murray walked away to join Djokovic’s team.

Should Djokovic win the Australian Open, he would become the first player to defeat the top three seeds to win a grand slam. After Alcaraz was knocked out, Zverev and Jannik Sinner stand in his way.

Only a few weeks after becoming a tennis coach, Murray will be behind a player in the semi-finals.

His actions on the court, and magnanimous gestures like consoling Alcaraz, have marked him out to be a serious figure in the role. It is not just for show; he has already had an impact on Djokovic’s matchplay.