The 31-year-old Serb is still wrestling with his own game as much as the man across the net, but there was plenty of evidence in his 6-4 6-7(6) 7-6(4) 6-2 victory to suggest he is approaching the form that earned him 12 grand slam titles.
There were the 51 winners and the way he dig himself out of a hole at the back end of the third set.
There was also the explosion of rage which saw him demolish his racket near the end of the second-set tiebreak.
"In these kind of circumstances, sometimes emotions get the worst out of you, you know, or the best out of you, whatever you want to call it," Djokovic, who is at his lowest seeding (20) in a Grand Slam for 12 years, told reporters.
"At times in my career, these kind of situations, when I would scream or throw a racket, it would kind of wake me up and help me to just kind of free myself from that pressure that is just building throughout the match."
Bautista Agut was the first to blink in the opening set after the first nine games went with serve.
Djokovic worked his way to 15-40 with some rugged baseline play and converted his second set point.
Thirteenth seed Bautista Agut, playing days after the death of his mother, battled back from 1-4 in the second set, breaking serve when Djokovic missed an easy volley and dragging the set into a tiebreak.
At 6-6, and having already saved two set points, Djokovic took aim at an open court with his forehand but his passing shot flicked the net and bounced wide, provoking the racket-smashing tantrum that earned him a warning.
His new racket looked in danger too when a baseline error allowed the Spaniard to level.
When Bautista Agut broke to love to lead 5-3 in the second set, Djokovic was rocking. But the survival instincts that have served him so well throughout his career came to the rescue.
He broke back, then never looked in danger in the tiebreak, bringing up set points with a flukey netcord that had him casting his eyes to the heavens.
Bautista Agut faded in the third set as Djokovic marched into the last 16 of a Grand Slam for the 43rd time, second on the all-time list behind Roger Federer.
After consoling his opponent at the net, Djokovic saluted the crowd who raised their colourful umbrellas in approval, clearly enjoying the 2016 champion's resurgence.
"I think for a set and a half and the fourth set, I have played pretty well. The fourth set was the best performance I have had in the tournament," Djokovic, who next plays Spanish left-hander Fernando Verdasco, said.
After some dark moments since completing his career grand slam at Roland Garros in 2016, the sky appears to be finally brightening for Djokovic who needed elbow surgery this year.
"You go through a rainbow of emotions. Every possible level of the colour of the rainbow, you go through it," he said.
"That's when you have to deal with this kind of emotions and understand how you can get better, how you balance everything that is happening inside so you can come out the next challenge and learn from it and be better."
