Pep Guardiola's men moved to the top of the Bundesliga on Tuesday with a dominant 4-0 win over newly promoted Paderborn.
The defending champions now face another newcomer in the form of Cologne in a game that Bayern will understandably be heavily favoured to win.
However, ahead of the visit to the RhienEnergieStadion, Sammer feels Bayern, who are likely to be without defender Jerome Boateng due to muscular problems, will need to take their game to another level to come away with all three points.
"A tough task lies ahead of us," Sammer said. "Cologne are very solid at the back and are a tight-knit team.
"A normal performance in Cologne will not suffice, we need a top performance.
"It feels good to be in first place, we're in top spot and don't want to move from there."
