DOHA, Qatar(AP) Roger Federer aims to stay the world's top-ranked player in 2010 after reclaiming the top spot from Rafael Nadal last year.

Federer, who will play his first match of the season Tuesday in the Qatar Open, says it was ``hard work'' returning to No. 1 last year.

Two-time Qatar champion Federer takes on Christophe Rochus of Belgium in his opening match.