Champions Bayern slumped to a loss at home to Cologne on Saturday in what was their third defeat in four games since the Bundesliga resumed after the winter break.

Bremen meanwhile went down to a last-minute goal to lowly Energie Cottbus and have managed just one point from a possible 12 since the season resumed.

Over a weekend of thrills and spills, all but one of Bayern's immediate rivals on the competition ladder faltered, unable to seize upon the defeat of Juergen Klinsmann's men.

Hertha Berlin had led at Wolfsburg but eventually lost 2-1, while Hoffenheim missed a stoppage-time penalty in an entertaining 3-3 draw against VfB Stuttgart.

Hamburg, however, rose to the top of the table after downing Bayer Leverkusen away from home, thanks to two unlikely goals from defender Marcell Jansen.

Hoffenheim's single point put them into second place on 40 points, ahead of Hertha on goal difference, while Bayern sit two points behind in fourth place and two points ahead of Bayer.

Important matchup

While Bayern still remain very much in the title race, Bremen, champions in 2004 and for so long Bayern's chief rivals, are on the slide this season. Both clubs now face a crucial week ahead.

Bayern play away against Sporting Lisbon in the Champions League on Wednesday, Feb. 25, and Bremen visit AC Milan in a battle for survival in the UEFA Cup on Thursday.

But of more importance to their domestic standings, the two clubs meet in Bremen on Sunday for their next Bundesliga encounter, and both will be desperate for a win.

Bayern will still be licking their wounds after their surprise slip-up at home to Cologne on Sunday. Juergen Klinsmann's side were hit twice on the break in the first half through Fabrice Ehret and Daniel Brosinski, though managed to pull back a late consolation goal through Daniel van Buyten.

"We're disappointed. A win would have put us top of the table. But we've also been lucky, as our rivals are still only just ahead of us," Bayern chairman Karl-Heinz Rummenigge said after the clash. "We've lost two in a row, and we need to get out of this rut very quickly, starting with Wednesday's game in Lisbon."

'We lost our cool'

Klinsmann brought in Lukas Podolski for the injured Luca Toni, but the Germany striker -- who is heading to Cologne at the end of the season -- could not impress and was replaced at half-time by US striker Landon Donovan.

"Not much went right for us today. We had the opening goal (from Miroslav Klose) disallowed, then we went behind and lost our cool," Klinsmann said.

"This is a really irritating defeat. Yet again, we've missed a chance to go top of the table. That's very bitter. Put simply, it was a poor performance."

Schaaf: Our own worst enemy

Bremen, meanwhile, would have hoped that their encouraging 1-1 midweek home draw with AC Milan might improve their chances of earning Bundesliga points over the weekend, but it was not to be at Cottbus.

Playmaker Diego was well shackled and despite taking the lead through Hugo Almeida, Bremen went down to goals from Ivica Iliev and Dimitar Rangelov. Bremen coach Thomas Schaaf said his side had only themselves to blame.

"Again we have allowed our opponents too many chances and again we have put a lot of effort into a game and got too little out of it," he said afterwards.

The defeat leaves Bremen in 11th place with hopes of European football next season fading fast. Although still nine points off the relegation zone, a defeat at home to Bayern would leave the team in trouble.

As it stands, the 21 rounds played so far this year represent Bremen's worst season since Schaaf and sports director Thomas Allofs took the reins 10 years ago.

Hoffenheim positive

Hertha meanwhile relinquished top spot after their defeat at Wolfsburg. The loss left them fuming after Edin Dzeko's winner six minutes from time was allowed although the striker appeared to push Josip Simunic as he headed the ball over the line.

"It's hard for us to take but referees are only human and make mistakes. I only hope something like that doesn't happen again," Hertha's Swiss coach Lucien Favre said.

The Hoffenheim camp remains upbeat despite missing out on the full three points against Stuttgart after Sejad Salihovic blasted over the bar from a stoppage-time penalty. Hoffenheim had taken the lead, but then were forced to twice come from behind in the 3-3 draw thanks to a hat-trick from Senegal striker Demba Ba.

Author: Darren Mara (dpa/reuters/bundesliga.de)

Editor: Trinity Hartman