Wildcard Denis Istomin, the world No.117, has incredibly ended Novak Djokovic’s dream of a record-breaking seven Australian Open titles this year with a gripping 7-6(8) 5-7 2-6 7-6(5) 6-4 victory in four hours and 48 minutes in just the second round at Rod Laver Arena on Thursday.

“It’s unreal,” Istomin said. “For me, it was impossible to think that I can hold it five sets with Novak, physically and mentally. So I did well today.”

“It means so much for me to beat the world No. 2.”

Djokovic himself was quick to praise his opponent. “All credit to Denis for playing amazing,” he said. “He deserved to win.”

“I'm not used to losing in the Australian Open second round,” he added. “I've always played so well. I've won six titles here. This court has been so nice to me. I enjoyed it very much. Of course, it's disappointing. But at the end of the day I have to accept it.”

One of the biggest upsets in Australian Open history, the match marked the first time in over a decade that Djokovic had been defeated in the first week, an even more unlikely occurrence given Istomin had only ever taken one set from the world No.2 – having played five times previously, including at Australian Open 2014, for a 1-12 return.

Where does Istomin's win rank in the Australian Open's biggest shocks?

Prior to Thursday, Djokovic had only lost once to a player ranked outside the top 100 in the past seven years, falling to No.145 Juan Martin del Potro at last year's Olympics. It was also his earliest exit at a Grand Slam since he fell to Marat Safin in the second round at Wimbledon in 2008.

All this counted for nothing as the pair began trading blows at Rod Laver Arena. The first game alone, on the Djokovic serve, lasted an incredible 16 minutes, with the Serb staving off six break points. The arm wrestling continued throughout the opening set, with the clean-striking Istomin looking increasingly threatening and eventually drawing first blood in the seventh game.

Fighting a vanguard battle, Djokovic pressed hard, and a rare flailed forehand from his opponent allowed him back into the set. Fittingly, a tiebreaker ensued – already breaking new ground for Istomin – but despite taking a 4-1 lead, the Serb was unable to capitalise as the Uzbek threw everything at him. It paid off as a loose return from the world No.2 sailed over the baseline handing Istomin – a former world No. 33 – the first set in an hour and 27 minutes.

The high level of tennis from both players continued in the second set and with Istomin serving at 72 percent to that point of the match, he maintained the upper hand. Three-quarters of an hour later, he stood on the brink of a potential two-sets-to-love lead with a pair of break points on the Djokovic serve.

However, in typical fashion, the Serb not only fought back but surged ahead to take the second set and level the match.

Things began to turn the Serb’s way from that point as he upped the offensive pressure and – simultaneously – Istomin began to tire after the nearly three hours already spent on court. The third set began with a slew of breaks, but eventually Djokovic began to expose the Uzbek’s increasing lack of mobility, and the challenge appeared to be snuffed out.

But as the shadows grew longer at Rod Laver Arena, there was to be a dramatic twist in the tale. Istomin unexpectedly came out firing to break Djokovic at the beginning of the fourth set and the momentum changed completely. Despite fighting cramp and foot complaints, he hung on grimly and out of nowhere, again found himself at set point.

Djokovic willed himself back into the contest, but the 30-year-old from Tashkent, gunning to take the biggest scalp of his career, eventually levelled the match again, decisively closing out the fourth tiebreaker with an ace.

With so much at stake and the match standing on the precipice, Istomin did not take a backward step, breaking Djokovic early in the deciding set and maintaining his advantage with poise and purpose, staying the course to snatch a stirring victory.

“Sometimes you have a good feeling,” Istomin concluded. “At this moment everything is good. The body, emotions, the game was in one.”

Istomin, who only found himself in the main draw after winning the Asia-Pacific Wildcard Playoff in Zhuhai, now enters the last 32 for the third time where he meets Spanish No.30 seed Pablo Carreno Busta, a straight-sets winner over Brit Kyle Edmund earlier on Thursday.

- David Packman/Australian Open