Late Kahlenberg goal gets Denmark up and running
Kahlenberg latched on to a pass from experienced forward Dennis Rommedahl to put Denmark second in Group H with three points from one game, behind Scandinavian rivals Norway who lead the way with six points from two matches.
Few other chances were created by either team in a dour game.
Denmark were missing young forward Nicklas Bendtner and first-choice goalkeeper Thomas Sorensen. The Danes next visit struggling Portugal, who are without a win from two matches, on October 8.