The top two meet next week at the Allianz Arena and Kovac is looking for a reaction on home soil.
“Now we must win the game against Dortmund,” he told reporters after the draw.
“I assume my players know what it is all about.
"We have to show Dortmund that we want to become champions and I expect us to put them under pressure and be aggressive next week.”
Reflecting on the game against Freiburg, Kovac lamented the host of chances missed by his side after the break.
“In the second half, we had to take advantage of one of our many chances," he added.
"What we got ourselves into is annoying.”
The draw against Freiburg continued a troubling trend for Kovac.
They remain one of only two Bundesliga clubs he has not beaten in league play as a manager, with current club Bayern the only other side on the list.
But Freiburg have proven a tough out for everybody in recent weeks, having lost just one of their last eight in league play while drawing five and winning two.
Dortmund are also on a fine run of form heading into next week’s showdown.
Prior to hosting Dortmund next Saturday, the champions have a DFB-Pokal clash against Heidenheim in midweek.