- Djokovic loses 7-6 5-7 2-6 7-6 6-4
- Istomin is ranked 117th
- Serb lost to a player outside the top 100 for second time since 2010
- Draw opens up for Andy Murray
Melbourne (CNN)The draw gods at the Australian Open had us all fooled.
There was us thinking Novak Djokovic's opening match against Fernando Verdasco would be tricky.
Instead, it was the second-round match that produced the upset -- and one of the biggest in tournament history -- when the bespectacled Denis Istomin of Uzbekistan ended the reign of Djokovic Down Under with a 7-6 (10-8) 5-7 2-6 7-6 (7-5) 6-4 win in a shade under five hours.
Just how massive a shock was it?
Consider that the 30-year-old Istomin, the world No. 117 and a wildcard, became only the second player outside the top 100 to defeat Djokovic in the last seven years. He so nearly lost in December's wildcard playoff, saving four match points in the semifinals.
The other conqueror wasn't a journeyman but rather Juan Martin del Potro, who upended Djokovic at the Rio Olympics in August. Del Potro's ranking only dithered because of repeated wrist issues.
Istomin's record against top-10 opposition entering the clash was a dismal won one, lost 32, and Rod Laver Arena is Djokovic's second home.
Half of his 12 grand slam titles have been clinched on Melbourne's centre court.
Djokovic hadn't lost this early at a major since falling in the second round at Wimbledon in 2008, a time when Roger Federer and Rafael Nadal were still at the top of the men's game.
"I'm as astounded as anyone else," former coach Boris Becker told CNN. "Novak was a bit too defensive, he never took the initiative and stayed too far behind the baseline.
"He looked good in Doha (two weeks ago), so I think he's done his homework, but obviously for him losing in the second round of the Australian Open is a big shock and has probably changed his year."
As dominant as Djokovic was from 2015 to the middle of 2016 -- bagging five grand slam titles including four in a row -- he has now suffered unexpected reverses in two of his three previous grand slams.
Will he ever regain his purple patch or is this the start of a prolonged slump at majors for Djokovic, who ended the partnership with Becker in the off-season after admitting that "private" issues previously affected his play?
"He has the talent and greatness but something that was there last year is missing, so he's got to sacrifice everything else for his next major, I think that's what he has to do," said Becker.
Andy Murray took advantage of his pal's slide to overtake Djokovic as the world No. 1 and will now be expected to end his title drought at the Australian Open given the departure of his main rival. Murray has fallen in five Australian Open finals, with Djokovic his tormentor on four occasions.
"I'm not used to losing in the Australian Open second round," said Djokovic, the two-time defending champion. "I've always played so well. This court has been so nice to me.
"Of course it's disappointing but I have to accept it."
There was nothing in Djokovic's outing against Verdasco that foreshadowed what was to come Thursday. Even before ousting Verdasco, Djokovic regained some momentum by ending Murray's 28-match winning streak in Doha.
But Istomin -- one of the few men's players coached by his mum -- put down a marker from the outset, stretching the Serb in a 16-minute opening game.
Overall, he hit 63 winners and 17 aces.
Still, when Djokovic saved two set points in the second set on his own serve and then took the set, few gave Istomin any chance of winning another set, let alone two.
Djokovic, however, let his opponent off the hook to begin the fourth, erring on a break point in the first game -- sending a routine forehand into the net -- and getting broken to trail 2-0.
Djokovic frequently lacked depth on his ground strokes and only intermittently did his serve provide respite.
Twelve months ago Djokovic tallied 100 unforced errors but escaped versus counterpuncher Gilles Simon -- he didn't get away with making 72 against the smooth, hard-hitting Istomin.
"I feel like the first couple of games of the fourth set, that's where it turned around," said Djokovic. "That's where I had my chances to step it up. I didn't.
"He started playing better from that point on. He just started swinging through and getting more confidence."
Istomin broke for 3-2 in the fifth and didn't waver, not facing a break point in the set. He sealed the match with a service winner down the middle.
"Denis was surely an underdog but he didn't show any nerves in the big moments," said Djokovic. "Surely he didn't play that many big matches but everything came together.
"It was the right moment for him, the right day. He was better."
Istomin broke his leg in a car accident in 2001 and his career was in jeopardy, so his perseverance was rewarded in a grand setting.
He joked that having his mum as his coach reduced his expenses.
"We have a good relationship and understand each other very well," he said.
Istomin will need to recover physically and mentally if he is to reach the fourth round of a grand slam for a third time. He meets Spain's 30th-seed Pablo Carreno Busta, who was spotted near the player restaurant shortly after Istomin's seismic win.
If Istomin was the man of the moment, Carreno Busta might be the beneficiary Saturday. Further afield, it could be Murray.
"It was a surprise," Carreno Busta told CNN, referring to the Istomin result. "Everybody thought Novak would win this match but it's tennis. You can win and you can lose.
"Istomin played really, really good.
"Tough match, four hours, 45 minutes."
A long day indeed, but a fruitful one for Istomin.