Out-of-form Nadal backs himself out of 'favourites' to win Oz Open

World number three Rafael Nadal has admitted that he is not among the favourites to win the Australian Open, saying that he lacks confidence on account of a back injury.

Making a comeback trail, the Spaniard started his 2015 campaign on a poor note as he was cruised past by German Michael Berrer in the first round of the Qatar Open.

Nadal, who is third seeded for the tournament, said that he didn't consider himself one of the favourites there, adding that he didn't feel himself ready to win the tournament there, Sport24 reported.

According to him, one cannot be a favorite of a tournament just by playing four to five matches in seven months.

Reflecting on his injuries, he said that he was confident about his knees as they were working very well, adding that he was not 100 percent confident on his back injury, the report added.

Nadal made a comeback in the Qatar Open after suffering a back injury in last year's Australian Open final and skipped last year's U.S. Open with a wrist complaint.