ABU DHABI (AFP) - Rafael Nadal shrugged off his 6-2, 6-0 defeat to Andy Murray at the Mubadala World Tennis Championships on Friday, insisting he'll be fighting fit when his 2015 season starts in Qatar next week.

The 14-time Grand Slam title winner was making his first appearance since undergoing an appendectomy late last year having also missed most of the second half of the 2014 season with a wrist problem.

The Spaniard's rustiness was obvious against Murray, who had played for more than two hours in seeing off Feliciano Lopez in his first match at the Abu Dhabi exhibition tournament on Thursday.

"This was not the best start possible against a tough rival in Andy Murray," the 28-year-old Nadal told the Gulf News.

"But there are only small things I need to adjust."

"6-2, 6-0 is too much. I had a lot of chances to have a closer result. I have to improve, that's obvious, and I'm going to improve. This match helps me and the defeat does not affect me too much.

"I felt I was dominating the points a lot of times, but I am missing competitive spirit. I am going to keep working hard to get that."

Murray goes on to face world No. 1 Novak Djokovic in Saturday's final after the Serb eased past Australian Open champion Stan Wawrinka 6-1, 6-2.

"I have been working very hard on my speed and movement around the court - maybe that made the difference," said Murray after his win over Nadal.

Wimbledon champion Djokovic was playing his first match in a month having completed his 2014 campaign by featuring in the International Premier Tennis League.

"I haven't played in over a month, so to play at such a high level against such a class player was nice," said the 27-year-old Djokovic, who won seven titles in 2014, including a seventh major at Wimbledon and the World Tour Finals in London.

Djokovic and Nadal will open their competitive 2015 campaigns at the Qatar Open in Doha from Monday.