After arriving without a competitive match in six months, the 12-times grand slam champion has had three impressive wins, including a taxing four-set scrap in broiling 40 degree Celsius (104F) heat against Frenchman Gael Monfils in the last round.
Djokovic goes forward to a third-round meeting with either 21st seed Albert Ramos-Vinolas or American Tim Smyczek.
"It's the beginning of the season". "It was really warm, it was tough to breathe".
"Recovery is not something I worry about with him", said Agassi, who added he is not working with Djokovic for "personal gain".
"It was right at the limit", Djokovic said.
Monfils saved two more match points, the second with a superb crosscourt forehand, but Djokovic converted at the fourth attempt with a simple volley.
'I was coming into the match knowing it was going to be a big challenge for both of us. "Obviously he wasn't at his best at the end of the second and the entire third set". I was just hanging in there trying to use every single opportunity.
"But at the same time I knew it was nothing major that can potentially raise a question mark on whether I can continue playing or not".
A decade after winning his first Melbourne Park title Djokovic has slipped to 14 in the world, his lowest in 10 years, but he has survived the opening two rounds in his comeback Grand Slam.More news: Second Women's March Draws Thousands, Focuses On Voting
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'There are so many players who could become the 26th holder of the Dubai Duty Free Tennis Championships trophy, with no player guaranteed of success in what is yet another world-class field, ' said Colm McLoughlin, Executive Vice Chairman and CEO of Dubai Duty Free, the tournament owners and organisers.
"It was tough to breathe".
Monfils said he may have had a heat stroke on the court.
That possibility has hung over him since the start of the tournament but has centred on his right elbow, which kept him out after he went out of Wimbledon on day nine last summer and nearly prevented him from returning to Melbourne, where he has had so much success. "I'm telling you, I was dying on the court for 40 minutes".
"I trained this winter in Miami. But I'm very pleased with where my game is at".
As for meditation, he said: "I don't want to tell you what I gain with it but I'll tell what I lose with it".
Djokovic, showing the effects of the struggle, fended off Monfils' renewed late effort and the Serb needed his fourth match point to claim victory.
No. 9 seed Stan Wawrinka, the 2014 Australian Open champion, No. 7 David Goffin and No. 13 Sam Querrey didnt make it through the second round.