Off-colour Bayern fell 2-1 at home to mid-table Köln on Saturday, the Bavarians' second league defeat in a row and their third in four matches since Christmas.
The 69,000 full house at the Allianz Arena saw the champions open brightly enough, only for Fabrice Ehret to open for the visitors midway through the first half. Matters took a serious turn for the worse when youngster Daniel Brosinski doubled the advantage ten minutes from the end of a nightmare 45 minutes for the champions.
The Köln defence stood firm against Bayern's increasingly desperate attacks for long periods of the second half, and although Daniel van Buyten finally threw his side a lifeline on 84 minutes with a firm header, it was a case of too little and too late on an off day for the champions, who remain fourth in the standings on 38 points from 21 matches.
Bayern boss Jürgen Klinsmann changed his line-up for the first time since the mid-season break, introducing three new faces to the side beaten 2-1 in Berlin last week.
Massimo Oddo and Daniel van Buyten replaced Christian Lell and the rested Lucio at right-back and centre-half, with Lukas Podolski starting his first match since November against his former and future club, in place of the injured Luca Toni (Achilles tendon).
After referee Babak Rafati whistled play underway on a freezing afternoon in Munich, Köln top scorer Milivoje Novakovic headed the first chance wide, before Podolski latched onto a loose ball in the box, only to direct his drive wide of the mark.
The visitors dropped deep after ten minutes as Bayern took over the initiative, probing away down the flanks. The home side were denied a perfectly good goal on 13 minutes when Klose buried Oddo's cross with his head only to be called back for offside, although replays showed the Bayern man was clearly played on.
Franck Ribery whistled a drive narrowly wide after outfoxing Miso Brecko down the left, before Bastian Schweinsteiger warmed Colombian keeper Faryd Mondragon's gloves from the edge of the box.
Köln in front
But the men from Cologne took the lead on 22 minutes when the ball spun away from a challenge between Novakovic and van Buyten, allowing French midfielder Ehret to gallop clear of Martin Demichelis and poke home past Michael Rensing.
Buoyed by the opener, Köln now counter-attacked with élan, Brecko testing Rensing from a tight angle after Ehret's neat through ball. The Rhineland side went two up after 34 minutes, Brosinski exchanging passes with Serb schemer Nemanja Vucicevic before collecting the return and netting from just six yards out.
Klose almost produced an immediate response, but the Germany striker missed the target with only Mondragon to beat. However, inspired by the cunning of Vucicevic, the visitors were on fire now as Novakovic began to cause the Bayern defence serious trouble. The Slovenia hitman blasted wide from 18 yards, before coming within a whisker of adding the third with a deflected shot from the left edge of the box.
Second half frustration
With his side trailing 2-0 at the interval, Klinsmann sent on Hamit Altintop and Landon Donovan for the anonymous Schweinsteiger and Podolski, but Donovan's first intervention was to clear another goalbound Novakovic effort off his own goal line.
Rensing saved a firm Brosinski drive, before Bayern finally upped their game on the hour in a desperate effort to salvage at least a point. Altintop and Ribery shot wide, and Mondragon saved from Klose and Ze Roberto, before Tim Borowski replaced the Brazilian for the last 25 minutes.
Daniel's effort too late
But despite their best efforts, it became an increasingly frustrating afternoon for the men in red, as a combination of the visitors' solid defence and biting tackles by Portuguese midfielder Petit saw most moves snuffed out well before reaching the danger zone.
Van Buyten rose to bury Altintop's cross with six minutes remaining, ushering in a frantic closing phase, but in truth Bayern deserved little reward on the day from a thoroughly below-par performance.
Live match report for fcbayern.de by Chris Hamley
|Bayern Munich - 1. FC Köln 1-2 (H-T: 0-2)|
|Bayern Munich||Rensing - Oddo, Demichelis, Van Buyten, Lahm - Schweinsteiger (Altintop 46), Van Bommel, Zé Roberto (Borowski 65), Ribéry - Klose, Podolski (Donovan 46)|
|Substitutes:||Butt, Lucio, Lell, Ottl|
|1. FC Köln||Mondragón - Brecko, Geromel, McKenna, Matip - Petit, Pezzoni - Brosinski (Sanou 76), Vucicevic (Boateng 90), Ehret (Broich 85) - Novakovic|
|Referee:||Babak Rafati (Hannover)|
|Goals:||0-1 Ehret (22), 0-2 Brosinski (34), 1-2 Van Buyten (84)|
|Yellow Cards:||Van Buyten, Oddo / Pezzoni, Brecko|