The four-time champion outclassed his rival from start to finish in the day's late encounter, producing over 30 winners in an exhibition of hard-court hitting.
Djokovic had begun the day by poking fun at tournament organisers, highlighted by this tweet about how hot the conditions are in Melbourne:
The Rod Laver Arena atmosphere is a little more hospitable, but Djokovic still would have been keen to exert as little energy as possible with one eye firmly on the latter stages of the competition.
He found his radar as early as the fifth point of the match, as shown by this incredible winner:
Djokovic broke in the third game, converting at the first time of asking thanks to an inaccurate backhand from Istomin.
The scores advanced to 5-3, at which point the defending champion broke again to clinch the set, despite Istomin hitting arguably the shot of the match with a running forehand slap.
Ironically, the winners column was the major difference in the opening stanza. Istomin could not buy a winner, hitting only two, including that incredible forehand, whereas Djokovic broke into double-figures in a classy set of tennis, per the tournament's official website.
Statistically, the match was already more-or-less beyond Istomin, as ESPN Tennis highlighted:
Djokovic has been crowned champion on his last three visits to Melbourne, and this year sees him chase his fifth Melbourne title overall.
Istomin lacked the agility and athleticism to live with the former world No. 1, and that will likely prove the case for all Djokovic’s rivals until he meets the likes of Rafael Nadal in the latter stages.
An injury to the Uzbekistani’s left leg would not have helped. He received treatment between sets, and Djokovic instantly threw in a couple of drop shots in the opening game to test his rival’s fitness.
The Serb was being applauded by new coach Boris Becker—added to the Djokovic staff ahead of the new season—whom he labelled a risk prior to the tournament, per Eleanor Crooks of The Independent:
Whenever you make a change in life, it's a potential risk. But I don't want to think from that perspective.
I'm really excited about this co-operation. I'm excited about this partnership that I have with Boris that also has been approved and supported by Marian (Vajda), who is still in the team.
There was certainly no risk of Djokovic losing this match. At 2-1 in the second, he advanced to 0-40 on the Istomin serve, breaking to love as his opponent cut a dejected figure on the other side of the net.
Losses of footing and restricted movement all counted against the world No. 49, as reported by the Australian Open's official Twitter account, and Djokovic served out to love at 5-3 to seal a two-set advantage.
The 26-year-old had won all three of the pair's previous meetings, and after only an hour and nine minutes on court, was well on his way to extending that record.
Anger had engulfed Istomin as he inexplicably challenged calls against him, and he wilted again to cede the advantage in the third game of set three.
He still showed some fight though, including this astonishing winner from way behind the baseline:
That fight delayed the inevitable as Istomin broke back with Djokovic serving for the match at 5-4, but the reigning champion eventually completed the type of routine victory he would have hoped for ahead of a Round 4 meeting with the maverick Fabio Fognini.