Roger Federer was presented with a crystal trophy to mark his record 161st consecutive week as world number one before beating Denmark's Kristian Pless 7-6, 3-6, 6-3 to reach the second round of the Dubai Open on Monday.

The former three-times champion, seeking to regain the title he conceded last year to Spanish number two seed Rafael Nadal, struggled a little when he began his Dubai campaign.

Federer had trouble getting on top of an opponent who served well and made few unforced errors.

The Swiss failed to take advantage of a break point in each of the Dane's first two service games, but he dropped only five points on his own serve as he took the first set in a tiebreak, which he took 7-2.

There was only one break in the second set and one in the third, both coming at 2-1. Federer made a forehand error to drop his serve in the second, and Pless did the same in the third.

"The guy played very well," Federer told reporters. "I knew it was going to be tough and I'm just happy I'm through, really. Losing my first set of the year doesn't matter much. The way I came through, I'm really pleased about it.

"The thing was to just try and get returns back into play and give myself opportunities. The worst is when you feel like you can't even say your forehand or backhand is bad because you're not playing any."

Fourth-seeded Spaniard Tommy Robredo found that adapting from an indoor tournament in Rotterdam to playing outdoors in Dubai was beyond him as he fell 7-6, 6-4 to wily French veteran Fabrice Santoro.

Sixth-seeded Czech Tomas Berdych dropped the opening set to 370th-ranked Kuwaiti wild card Mohammed Al Ghareeb but recovered to win 3-6, 6-3, 6-2, and Slovak Dominik Hrbaty took just 56 minutes to overwhelm Omar Bahrouzyan of United Arab Emirates 6-1, 6-2.

Bahrouzyan, who has never won a set in his seven appearances in the event, four times double-faulted on break points, and Hrbaty needed to make only two forehand and two backhand winners in the entire match.