The Bundesliga's fifth-placed side have not won in four league matches, but could close the gap on their second-placed opponents to four points with victory.
However, Favre knows his side are also playing against history, with Gladbach having failed to win their last 21 league matches at home against Leverkusen - a run that stretches back to 1989.
"It's about time we beat them here," the trainer told reporters. "We've lost two in a row and certainly not played as well as we can. But we've now got to remain calm.
"Only small things make the difference and we've just been creating too few chances compared to the first half of the season.
"Just let's not forget that we got 33 points in the first half of the season."