It was the first title for the 29-year-old Russian since St. Petersburg in 2010.
Youzhny faced no break points and lost only 12 points on serve during the 68-minute match.
After both players won opening service games, Youzhny won eight of nine games, winning the first set and three games in the second.
Lacko then kept his serve until the end of the match but could not challenge Youzhny.
"This was my best match of the tournament," Youzhny said. "I gained some confidence here but I don't want to think about whether I will be in the top 10 again or not."
Playing in his first final, Lacko admitted he was "dismissed badly."
Lacko reached the third round at the Australian Open as a qualifier, but was ousted by Spaniard Rafael Nadal. He had never previously advanced beyond the quarterfinals at an ATP event.