Miami: Six-time champion Novak Djokovic "ran out of gas" in a 6-3, 6-4 loss to Benoit Paire on Friday in his ATP Miami Masters opener.

It was another setback for the Serbian star as he bids to return from the elbow injury that sidelined him for six months and finally saw him have "minor" surgical intervention after a disappointing Australian Open.

"I'm trying, but it's not working," Djokovic said. "That's all it is. I mean, obviously I'm not feeling great when I'm playing this way. Of course I want to be able to play as well as I want to play. Just, it's impossible at the moment. That's all."

Paire broke Djokovic at love to seal the win, Djokovic dumping a backhand into the net on the Frenchman's first match point.

Paire broke Djokovic in the seventh game of the opening set -- part of a run of five straight games that saw him take a 6-3, 1-0 lead.

"I felt I started the match well, first six games," Djokovic said. "Then I just ran out of gas. He was serving well. I just wasn't able to break him down. He was just coming up with the good shots at the right time. It happened very fast."

Djokovic, the former world number one now ranked 12th in the world, dug deep to escape a 0-40 hole and hold serve in the second game of the second set before Paire broke him for a 4-2 lead.

Djokovic responded with his first break of the match to put the set back on serve, but simply had no answer in the final game.

Djokovic had also lost his opening match at the Indian Wells Masters last week. But he was encouraged in Miami this week to find himself playing without pain for the first time "in years".

He said a lack of match fitness was "one of the things" preventing him from gaining any steam in his bid to return to his top form.

But he said that in attempting to play through injury for so long, "I compromised my game and the movement and everything ... I'm trying to figure things out.

"I wanted to come to Indian Wells and Miami because I wanted to see whether I can play a match," he said. "I love playing on the hard court. I wanted to get a couple of tournaments before the clay court season starts.

"I obviously wasn't ready for that."

Although he had planned for the two Stateside hardcourt tournaments to be a precursor to a full clay court season, Djokovic sounded unsure after the defeat.

"That was the plan," he said when asked if he felt ready to head into the Monte Carlo Masters Aril 14-22. "But let's see what happens."