Novak Djokovic vs. Denis Istomin: Score and Reaction from 2017 Australian Open

Defending champion and world No. 2 Novak Djokovic was knocked out of the 2017 Australian Open in the second round by world No. 117 Denis Istomin on Thursday in one of the biggest shocks in the tournament's history.

After four hours and 48 minutes of scintillating tennis, Uzbekistan's Istomin prevailed 7-6 (8), 5-7, 2-6, 7-6 (5), 6-4 to secure a spot in the third round at the year's first major. 

Djokovic acknowledged after his defeat that Istomin was the better player on the day, per the Australian Open:

To get a sense of just how grueling the second-round affair was, look no further than the first set. 

The 85-minute opening frame was a back-and-forth drama rife with tension, and Djokovic grew visibly frustrated with his inability to shake the pesky challenger during the early proceedings. 

Istomin continued to press Djokovic's buttons, and he converted a couple of sensational forehands to further fluster the world No. 2 and steal the first-set tiebreak 10-8. 

According to the New York Times' Ben Rothenberg, Istomin's early statement was surprising since he wasn't even a lock to participate in the year's first major a month ago: 

Djokovic continued to look out of sorts at the start of the second set, where his passivity came as a surprise to ESPN's Brad Gilbert: 

To that point, Istomin used booming baseline power to his advantage. The world's 117th-ranked player kept Djokovic in a frazzled state for an extended stretch, which forced the favorite to chase the ball across the court while his opponent picked his spots and flirted with a shocker, as Gilbert observed: 

But just when it looked like the Serb was headed for a 2-0 deficit, he came up with a monster break to move ahead 6-5 in the second stanza and knot the match at one set apiece.

According to Metro's George Bellshaw, that resilience in the face of competitive distress was vintage Djokovic:  

Momentum started to build bit by bit for the six-time Australian Open champion in the third set, and a trio of breaks allowed him to cruise to a 6-2 victory and a 2-1 lead overall. 

Although Djokovic appeared to have Istomin on the ropes at that point, the underdog refused to back down. The Uzbek player scraped together a break point on his opponent's first service game of the fourth set, and he even worked his way to a set point up 5-4. 

Djokovic saved set points to briefly keep dreams of a four-set victory in sight, but Istomin answered the call in the tiebreak. 

It was then Istomin who took control in the decider. After a couple of tricky holds for the underdog, he carved out two break points at 2-2 and took the second with a fantastic backhand winner down the line.

He then grew in confidence, holding easily to get to 5-4 ahead and find himself serving for the biggest win of his career. 

Incredibly, he showed no sign of nerves and took the first of his two match points to claim a deserved win over six-time champion Djokovic.

Stats courtesy of ATPWorldTour.com and AusOpen.com.