Denis Istomin scripted the mother of all upsets in the Australian Open on Thursday, sending defending champion and World No.2 Novak Djokovic packing in an absorbing five-set tie that lasted close to five hours.

The final scoreline read an impressive 7-6 (8), 5-7, 2-6, 7-6(5), 6-4 in the 119th-ranked Istomin’s favour, as he won the biggest match of his career, ending his five-match winless streak against the Serbian in style.

Arguably the best match of this year’s Australian Open so far, Istomin was unplayable at times, sending in aces when facing break points with consummate ease, stymying Djokovic time and time again.

Djokovic was broken early in the first set but bounced back to break Istomin and eventually it went to a tiebreak in which the Russian managed to prevail. His ability to send in unplayable serves at crucial points really left the second-seed bemused as he tried to get a vital breakthrough. The tie-break seemed to go on and on, until finally Istomin won it 10-8.

The Serbian, who has been notorious for starting slowly at Slams, then won the next two sets to take a 2-1 lead in the tie, but was made to work for every single point. It took him until the 11th game to finally break the troublesome Uzbek, capitalising on the breakthrough to level the tie at one-set all.

While the third set read 6-2 in Djokvovic’s favour, suggesting an apparent ease, even then the Serbian was broken once but Istomin’s inconsistent serves lost him the set to give the defending champion a decisive advantage in the tie.

A six-time champion at Melbourne, Djokovic didn't really look out of sorts, such was Istomin’s brilliance on the day.

The unranked player had a 4-1 lead in the third set, before Djokovic charged back in to level the scores at 4-4, but the second tiebreak again went in the Uzbek’s favour, this time rather tamely.

The stage was set for a fifth and final set, but most fans were cheering for Djokovic to pull through, as a second round seemed unthinkable. Yet, that is exactly what happened, as the Serbian exited the competition at such an early stage since winning his maiden title in 2008.

Istomin broke the Djokvoic early in the final set, setting in a bit of an anti-climax, with the crowd slowly coming to terms that an historic upset was on the cards.

And as Djokovic committed yet another uncharacteristic era, a roar went up in unison, with the entire Rod Laver Arena applauding a unique moment in Australian Open history.

His reward for the exhilarating win is a third round tie with Pablo Carreno Busta of Spain, but this win over Djokovic will be a cherished memory, regardless of the outcome of that encounter.