Dortmund, who have 42 points, face a tricky trip on 19 January to fourth-placed RB Leipzig.
"Hoffenheim are dangerous," said Kovac on the eve of the clash. "We found that out in our last match when they equalised and we had to work hard to win the game.
"It will be tough and we need to win to keep the pressure on Borussia Dortmund."
Kovac, who took over from Jupp Heynckes in July 2018, cited the ankle injury to French winger Kingsley Coman as one of the key reasons for Bayern's failure to keep level with Dortmund.
"I have to admit the loss hit us hard," said Kovac. "Although it's impossible to prove, I think if Coman had not been missing, we wouldn't have dropped so many points in the first half of the season and maybe we would be top of the table."
The 22-year-old France international returned to action at the end of the year and is expected to start the match against Hoffenheim in the absence of the injured veteran Franck Ribery.
"He is fit and doesn't feel any pain," added Kovac. "That's very important and because Arjen Robben's also out. I expect Kingsley to take over and bring his skills."