Bayern Munich opened up a seven-point lead over their nearest challengers thanks to Leon Goretzka’s first half effort.
With just seven games of the season left to play, Bayern are on course to wrap up a ninth straight Bundesliga title.
Nagelsmann has admitted Bayern’s lead is insurmountable at this stage of the season and will be content with a runners-up spot.
"It’s not a goal we should be conceding, but we still played very well," Nagelsmann told Sky Germany after the game.
"We pushed Bayern deep into their own half at various stages, but not for the first time this season we didn’t score. We have to learn from that.
"It’d help if we had a proper goal-getter, but we don’t. We were the better side, but have to make more of our chances. Now we have to let it sink in and get on with it.
"If the season goes as expected, Bayern will be champions. We want to finish second."
Leipzig captain Marcel Sabitzer echoed the words of his manager, adding: “We only have ourselves to blame for that. First we have to digest what happened. We want to finish second, and reach the German Cup final."
