Michael Berrer serves upset against Rafael Nadal in Qatar
Michael Berrer of Germany returns the ball to Rafael Nadal of Spain during their match at the Qatar Open tennis tournament in Doha January 6, 2015. Reuters

It’s the worst possible start for Rafael Nadal in the 2015 Association of Tennis Professionals (ATP) season. The Spaniard suffered an upset loss to unknown tennis pro Michael Berrer from Germany in the opening round of the 2015 Qatar Open in Doha, Qatar on Tuesday with a final score of 1-6, 6-3, 6-4 in a match time of 1 hour and 56 minutes.

Nadal blamed his nerves and lack of competition after being injured in the second half to the 2014 ATP season. Nadal, who had a 48-11 win-loss record in 2014, had to go through a trying season struggling with a wrist injury around July and then had an appendectomy in November.

''These things happen after long time without being on the road, being on rhythm, being in competition. I was playing with more nerves because after long time [away] I wanted to win. When you are back from an injury, that takes time,” The Spanish star stated to The New York Times. "I'm going to work hard to try to make it less tough as possible. My motivation and my hunger to keep doing things well is still the same.So I am sure that I'm gonna come back to my best. I hope to be soon.”

Nadal lost to Nick Kyrgios of Australia in the Round of 16 stage of the 2014 Wimbledon Championships last June and has since struggled in all of the tournaments he has joined. Nadal lost in the quarterfinals of the Beijing Open to Martin Klizan (Slovakia) in September, in the Round of 32 of the ATP World Tour Masters Shanghai to Feliciano Lopez (Spain) in October and then in the quarterfinals of the Swiss Indoors Basel to Borna Coric (Croatia). With his performance in Doha, Qatar, it appears Nadal has yet to gain the form worthy to be called a top contender in the men’s singles competition in tennis.

Berrer, a 34-year-old German qualifier for the event, was expectedly ecstatic with the upset win calling the win “unbelievable”. Berrer, who is ranked 127th in the world rankings, advances to the second round against Croatia’s Ivan Dodig, who beat Mohamed Safwat in the first round.

Unlike Nadal, who was the second seed in the Doha tournament, other top seeds had little trouble dispatching their opening round opponents. World no. 1 Novak Djokovic of Serbia beat compatriot Dusan Lajovic, 6-2, 6-1, No. 3 seed Tomas Berdych (Czech Republic) defeated Denis Istomin (Uzbekistan) and No. 4 seed David Ferrer (Spain) defeated Thiemo De Bakker (Netherlands), 6-7, 6-4, 6-3.

To contact author of this article, email j.gloria@IBTimes.com.au