Djokovic suffered an unwanted career first when he failed to convert three consecutive match points in a pulsating 6-2 2-6 7-5 singles loss against world No.4 Sinner.

It was Djokovic’s first defeat in a Davis Cup singles rubber since a retirement against Juan Martin Del Potro 12 years ago, ending a 21-match winning run.

Serbia had led 1-0 in the semi-final in Malaga thanks to Miomir Kecmanovic’s win over Lorenzo Musetti but Djokovic’s loss sent the tie to a deciding doubles contest.

Djokovic and Sinner lined up on opposite sides of the net for the fourth time in less than two weeks alongside Kecmanovic and Lorenzo Sonego respectively, and it was the Italian duo that clinched a 6-3 6-4 win to send its country through to a clash with Australia for the title on Monday (AEDT).

After Kecmanovic had backed up his fine showing against Britain’s Jack Draper by coming from a set down to defeat Musetti 6-7 (7) 6-2 6-1, the stage seemed set for Djokovic to send Serbia through to the final.

The confidence Sinner had gained from his group stage victory over Djokovic at the ATP Finals was negated by a convincing loss in the final but the world No.1 looked fatigued, perhaps more mentally than physically, during the first set.

Both men had headed straight from Turin to Malaga but Sinner is 14 years younger than his rival and he took full advantage of some uncharacteristic errors to reel off five games in a row.

It was another excellent atmosphere at Palacio de Deportes Martin Carpena, befitting the sort of marquee clash that Davis Cup has not seen enough of over the past decade and more.

Djokovic had made winning a first title with Serbia since 2010 one of his big priorities and he showed more positive energy at the start of the second set, breaking for the first time to lead 3-1 after his opponent double-faulted.

A second break sent the contest to a deciding set, where it seemed a case of when rather than if Djokovic would find the breakthrough.

But Sinner refused to buckle, saving break points in two separate games prior to his remarkable renaissance at 4-5, when he won five points in a row from 0-40.

The missed opportunities seemed to play on Djokovic’s mind and, in a reminder that even the very best are not immune to pressure, the Serbian netted a routine shot to hand Sinner a break point and was then passed after an ill-advised serve and volley.

Moments later, Djokovic blasted a return long to the sounds of Italian jubilation and stunned Serbian silence, with Sinner saying: “It was an incredible match. We were one point away from being out of the competition but we are still here.”

Djokovic’s singles record in Davis Cup may be formidable but his doubles one is anything but, with only four wins from 11 previous matches.

None of the four players picked are regulars on the doubles circuit but the Italian duo looked much more at home in the format and broke Djokovic’s serve on the way to taking the opening set.

It was a break up early in the second, too, but this time Serbia came back and, having lost his cool with the British crowd on Friday (AEDT), Djokovic began conducting the Italian jeers.

After Sinner saved four break points to hold for 3-3, another long game, this time on the Kecmanovic serve, resulted in a break for the pumped up Italian pair, and fittingly it was Sinner who served out the victory.