Acapulco, Mexico (AFP) - Novak Djokovic said Monday he is ready to atone for his shock Australian Open exit as he prepares to return to action in Acapulco.

The 29-year-old world No. 2 makes his bow in the tournament on Tuesday, his first match since tumbling out last month in the second round against Uzbekistan's Denis Istomin.

The Australian Open defeat was the nadir of a challenging dip in form for the Serbian former world No. 1, who has won only two titles since July last year.

Djokovic, who is making his debut in Acapulco, said he feels in a healthier frame of mind since his travails of recent months.

"All in all, I feel that I'm in a much better state of mind than maybe I was at the end of last year. So I keep on going. I love this sport. That's why I'm playing it. That's why I'm here. I'm just hoping that I can stay healthy and as dedicated as best as I can be," Djokovic said.

Djokovic, who plays Slovakia's Martin Klizan in the first round, admitted going out in Melbourne so early had come as a shock.

"I haven't experienced the first-week Australian Open loss for many years," said Djokovic.

"But it's kind of normal and expected to go through those times when you're not playing as best as you can maybe, as best as you want to be, or maybe the opponent has an amazing day. It's sport. You have to deal with it, and you can always learn much more from the losses."

In early round action on Monday, American eighth seed John Isner was upset by compatriot Steve Johnson, going down in straight sets 6-4, 6-4.

Fifth seed Belgian David Goffin had no such difficulty however, breezing past France's Stephane Robert 6-1, 6-2.