MELBOURNE, Australia (AP) -- Rafael Nadal said he's ''working as hard as I can'' to be ready for Monday's start to the Australian Open following a right wrist injury and appendix surgery which sidelined him for most of the last six months of 2014.

Nadal went through a strenuous workout at Melbourne Park on Wednesday, followed by a two-hour exhibition match against Mark Philippoussis and Fernando Verdasco as part of a charity night to open the renovated Margaret Court Arena, the Australian Open's third court with a retractable roof.

On Thursday, Nadal said he recovered well from the tough day of workouts, but added it would be difficult to quickly reach the level of fitness to win the title this year.

''I'm back, and I'm healthy, but it's hard to come back after such injures,'' Nadal said. ''I will hope for first round, second round, and take the wins as they come.''

Nadal was knocked out in the first round at Doha two weeks ago by a qualifier, but then teamed up with good friend, Juan Monaco of Argentina, to win the doubles title, giving him some valuable court time.

''To start the season with a title, even if it's only in doubles, is a great feeling,'' the 14-time Grand Slam champion said in Doha. ''When you lose early in singles it's a good way to still be in competition. A win is always a good feeling and to have that feeling again was very positive.''

Nadal had played only seven singles matches since Wimbledon before arriving in Doha.

''It was an important week because I came back to the tour after a long time not being competitive,'' Nadal said. ''I lost in the first round in a match that can happen. I'm going to work hard to be ready for Australia but if that doesn't happen I'm going to keep working hard to be ready for Rio, then Buenos Aires and Indian Wells and Miami.''

The third-seeded Nadal will find out on Friday who he will be face first.