DOHA  - Spain's Rafa Nadal had to fight hard not to lose his opening match of 2012, going a break of serve down in the final set before surviving against an opponent ranked outside the top 40 in the Qatar Open here on Tuesday.

The French Open champion fought back with typical courage in his 6-3, 6-7 (2/7), 6-3 win over Germany's Philipp Kohlschreiber but it was a patchy performance which left an impression that tennis is a bit of a struggle for him at the moment.

Nadal found it hard to achieve rhythm and consistency with his ground strokes, sometimes leaving the ball short, and allowing his intensity to subside surprisingly during a second set spell when he went 1-4 down.

But after dropping serve in the first game of the final set, the world number two began to hit some more solid blows, particularly with inside out forehands taken from the backhand corner, and finished looking much more in charge. "I didn't have a chance to practise much, I had problems with my shoulder and knee, and arrived feeling so-so," Nadal said, referring to an off-season curtailed by the late finish of the 2011 Davis Cup. "So a victory was very important. The beginning was a bit risky but I came back well and played a bit more aggressive."

This was not though the Nadal depicted in his new year resolution, one who aims to become more permanently an aggressive player, taking the ball on or inside the baseline at every opportunity.

But Nadal, who next plays another German, the qualifier Denis Gremelmayr, believes his shortcomings were just some of the normal difficulties in re-acquainting himself with a tennis match. He later came up with a more positive interpretation.

The second-seeded defending champion from Switzerland needed less than an hour to get past the former champion, Nikolay Davydenko, by 6-2, 6-2. Federer admitted he surprised himself with the level of his performance against the Russian opponent who beat both himself and Nadal while winning the 2010 title here.

He next plays Grega Zemlja, a qualifier from Slovenia who won 4-6, 6-1, 6-1 against Sergei Bubka, a wild card entrant who is the son of the Soviet pole vaulter (of the same name) who was repeatedly voted the world’s best athlete. Later Gael Monfils, the fourth-seeded Frenchman, joined his compatriot Jo-Wilfried Tsonga in the second round when he won 7-5, 6-3 against Rui Machado, the world number 67 from Portugal. Monfils, a finalist here six years ago, quickly recovered from the disappointment of failing to close out the first set on his serve at 5-4, combining his familiarly brilliant court coverage with an increased ratio of attacking at the net.