Belgian Bailly fisted the ball into his own net from a corner just past the hour to leave the home team anchored on 23 points, five off the relegation play-off spot. Kaiserslautern climbed to 12th place on 31.
With both teams playing cautiously, knowing any mistake might prove costly, chances were few and far between in the first half.
Kaiserslautern's Rodnei cleared a Martin Stranzl shot off the line and minutes later at the other end the Brazilian defender almost scored when his header hit team mate Mathias Abel.
Christian Tiffert then went close with a low drive for the visitors.
‘After Manchester City’s recent form, maybe they’re the underdogs against Manchester United!’ Former Red Devils defender on this weekend’s derby
‘Arteta, Alonso, Emery, me… none of us were physical players – we needed the understanding of the game. That probably helped us move into management’: Premier League boss reveals reasons for natural career progression
