Bayern Munich underlined why they are the reigning German champions bouncing back from their recent slump to crush old foes Borussia Dortmund 4-1 at the Olympic Stadium on Sunday and stay in touch with the pretenders to their Bundesliga crown.

Defeats to Schalke 04 and Lyon in the Champions League prompted coach Ottmar Hitzfeld to label the Dortmund encounter a "must-win game" and Bayern delivered with a display full of enthusiasm and attacking imagination to collect a vital three points after VfB Stuttgart, Bayer Leverkusen and Werder Bremen all won over the weekend.

"We started energetically and drove forward from the first whistle," explained Hitzfeld. "We should have gone ahead earlier but for the misfortune with the woodwork.

"But we have taken our first step out of the mire."

Dortmund's defeat sees them surrender fourth place to Bayern as their Olympic Stadium jinx continues with the 2002 Bundesliga winners yet to taste victory at the venue since October 1991. "Conceding three goals from set pieces is not good enough," raged Dortmund coach Matthias Sammer.

"We shot ourselves in the foot."

With the criticism still ringing in their ears Bayern's stars started at a high tempo and incredibly hit the woodwork three times in the first seven minutes.

Michael Ballack, Roque Santa Cruz and Roy Makaay all came within centimetres of opening the scoring only to be denied by the goalframe.

When the returning Sebastian Deisler hit the crossbar again with a dipping shot on 19 minutes Bayern must have feared it was not going to be their day.

But Ballack headed home seven minutes later to hand the champions a deserved lead.

An explosive second half then saw Dortmund draw level with Czech striker Jan Koller taking advantage of an awful Bixente Lizarazu clearance to volley home.

Parity was shortlived though as Frenchman Willy Sagnol atoned for the error of his compatriot sixty seconds later with an unstoppable header to restore Bayern's lead.

The visitors' vulnerability in the air was highlighted once again in the 72nd minute when the diminutive Hasan Salihamidzic headed home before substitute Claudio Pizarro put

some gloss on the win with an effort in injury time.

Stuttgart continue to lead the way after an away win over Eintracht Frankfurt 2-0 on Saturday.

Bayer Leverkusen's title challenge continues to gather pace following Sunday's 3-1 over Schalke 04 at the BayArena.

It broke Bayer's home hoodoo against Schalke - who had won their last three matches at the venue - and moved Bayer to within one point of Stuttgart in second place.

Werder Bremen also stay in the title hunt after hammering Hannover 5-1 on Saturday and emphasising that they are not a one-man team.

Elsewhere, Klaus Toppmoller was handed his first Bundesliga win since taking charge of SV Hamburg as his side triumphed 3-1 over 1860 Munich at the AOL-Arena.