MASON, Ohio,  (Reuters) – Andy Roddick needed three  sets to beat 46th-ranked Ukrainian Sergiy Stakhovsky 6-4 6-7  6-1, while fellow American Taylor Dent upset Feliciano Lopez to  advance to the second round of the Cincinnati Masters yesterday.

Roddick, who has struggled for form and fitness in recent  weeks, produced some powerful serves but had to stay alert  against an opponent who played some enterprising if erratic  tennis.

The Ukrainian came out on top in the tiebreak at the end of  a very tight second set but Roddick broke early in the third to  take a firm grip on the match.

Dent, who last won an ATP tournament in 2003, beat Spaniard  Lopez 6-3 6-2 in perfect conditions on center court to set up a  second-round clash with world number one Rafa Nadal.

Switzerland’s Stanislas Wawrinka comfortably defeated  Spaniard Nicolas Almagro 6-3 6-3 and will play the winner of  the all-French match between Michael Llodra and Julien  Benneteau.

Sam Querrey completed a good day for the United States by  beating German Phillipp Petzschner 6-1 6-4.