By ESPNSTAR.com staff
Leverkusen took the lead in the first half via Stefan Kiessling before Mario Mandzukic levelled the score in the 77th minute. Sidney Sam then broke Bayern hearts with a late goal three minutes from time.
Lahm felt that both goals conceded by his side were preventable and rued the result, which is the first time Bayern failed to pick up all three points in the league this season.
"Leverkusen's victory isn't undeserved, because they scored two goals," Lahm was quoted as saying on the official Bayern website.
"We let in a ridiculous and stupid opening goal, we fought back and made it 1-1, and then we let in an equally dumb second goal."
Manuel Neuer was also disappointed with Bayern's defeat, but was adamant that the loss had nothing to do with their attitude.
"We should perhaps criticise ourselves for not taking the lead. At the start, Leverkusen came here and tried to play football, but we should have scored the first goal.
"Instead we were forced to come from behind. We gave it everything we had in the second half and tried to salvage something. The defeat wasn't due to our attitude."
Bayern are still top of the table despite the loss and lead second-placed Schalke by four points.