Hansi Flick feels Bayern Munich paid for the price for being too conservative in the first half of their 1-1 draw against Union Berlin and acknowledged his side "can definitely play better".

The Bundesliga champions trailed after just four minutes of Saturday's contest at Alte Forsterei as Grischa Promel headed the underdogs into a shock lead.

Robert Lewandowski's 16th goal in as many games this season levelled proceedings just after the hour but Bayern were unable to find a winner in an entertaining clash.

"The first few minutes we were not present on the pitch as we had wanted to be. We could have defended better when we conceded the goal, without question," head coach Flick said in quotes reported by Bayern's official website.

"When the first ball becomes dangerous, our composure is not there. We played the safe pass or a long ball. I wasn't too happy with that. We addressed that during the break.

"We wanted to play with more composure and occupy space better in the second half, to have men over. I was more satisfied with the second half. We can definitely play better.

"Our idea is to put the opponent under pressure. Today we weren't able to implement it as we had planned. It will be a difficult season, we knew that in advance.

"Now we have to take the positives from the situation and improve on the things that didn't go so well."

Bayern, who are top of the table on goal difference ahead of RB Leipzig after 11 games, have now fallen behind in each of their past five Bundesliga matches - a trend forward Thomas Muller is keen to buck.

"We've often gone a goal down recently. It happened very early today. Union fought hard and played man-to-man," Muller said.

"We made life difficult for ourselves, especially in the first 20 minutes. We need momentum again and to bounce back again.

"We have the quality, mentally too, but of course it just happens that we not winning but rather drawing matches. It feels too little given our ambitions."