Following five defeats in six warm-up games and whistles from their own fans, Carlo Ancelotti's Bayern Munich have something to prove at Borussia Dortmund on Saturday for the German Super Cup.

As defending Bundesliga champions, Bayern face German Cup-winners Dortmund at a sold-out Signal Iduna Park with recent results suggesting the Bavarians are far from ready for the annual pre-season showdown.

"We have to win, this is an important game for FC Bayern," said French winger Franck Ribery defiantly, but they have not been convincing of late.

Bayern were booed at by their own fans at the Allianz Arena in Wednesday's 2-0 defeat to Napoli, a day after their 3-0 trouncing in Munich by Liverpool, which left them last in their own pre-season tournament.

Germany defender Mats Hummels said the Liverpool defeat was the worst he had "ever experienced with Bayern" while head coach Ancelotti admitted recent results are a concern.

"We know we're not in the best physical condition," said Ancelotti, who expects a "difficult, intense game" in Dortmund.

"The most important point is the balance in the team, which has not been good."

The back-to-back defeats in Munich followed loses to AC Milan and Inter on their pre-season tour of China and Singapore, plus a penalty shoot-out defeat to Arsenal and a slender win over English champions Chelsea.

Bayern will not be at full strength in Dortmund.

New signing James Rodriguez is out for the next few weeks with a hamstring injury and attacking midfielder Thiago Alcantara will miss the Super Cup game with a stomach muscle injury.

Goalkeeper Manuel Neuer only recently returned to training after foot surgery, so Sven Ulreich will deputise in goal with Thomas Mueller captaining the team.

Defender Jerome Boateng and veteran winger Arjen Robben are both lacking fitness, while Ancelotti confirmed Friday that left-back David Alaba is also out with a knock.

Dortmund will also be something of an unknown quantity after losing three of their six pre-season matches.

After Thomas Tuchel was sacked just days after winning the German Cup final, new head coach Peter Bosz faces his first real test at home.

"We're making progress. I can see that we have a better understanding of what is asked of the players. That pleases me," said the Dutchman.

Bosz dismissed Bayern's recent poor results and rejected any notion of a "pre-season crisis".

"I don't believe that Bayern will finish last this season and we'll be second from bottom," said the ex-Ajax coach.

"The fact that neither team is where they expect to be is clear.

"We want to win the cup and will give our best in front of our own fans."

A crowd of 80,000 is expected and Germany's attacking midfielder Mario Goetze is expected to return after being sidelined for the last five months by a metabolism disorder.

"Goetze needs time, he needs the rhythm, he's on a very good path," said Bosz.

Teenager Jan-Niklas Beste, 18, could make his home debut after the Germany Under-17 international left-back impressed Bosz in training.