The Spanish left-back arrived last week.
"Having genuine competition for places is really healthy and, in fact, vital for any club that aspires to bigger and better things," Lambert told Villa's website.
"For instance, Antonio Luna has come in and he will augment and enhance the defence and give us some more options there.
"He's played about 70 games in Spain and we all know the standard of football in La Liga.
"We know that defensively we need to improve from last season, overall as a team, so that's good."