Dortmund's implosion in last weekend's 4-2 defeat to rivals Schalke appeared to hand Bayern Munich a huge boost at the top of the table, but the champions failed to take advantage as they were held to a surprise 1-1 draw by relegation-threatened Nurnberg the following day.
The gap between first and second now stands at two points and the sudden change in fortune has given Favre and his players renewed hope of erasing the deficit.
"Everybody thought that it was over. Not just me, everyone did," Favre said in his pre-match news conference.
"It wasn't planned that Bayern would struggle against Nurnberg.
"The players are not stupid. They look at the table and know everything's possible again, but we need to focus on the game against Bremen and need to win it.
"There's no other way."
Dortmund with Reus vs. Without Reus this season: 69% win rate vs. 60% win rate— Bundesliga English (@Bundesliga_EN) May 2, 2019
Werder with Moisander vs. Without Moisander this season: 25% of games lost vs. 66% of games lost
Big players to miss this weekend pic.twitter.com/EQTQdGkZbx
Marius Wolf was handed a three-game ban after being sent off in the same game and could be replaced at right-back by the experienced Lukasz Piszczek, who is on the cusp of returning from injury.
"It doesn't do much good to talk about it. Fortunately, he will be available for the last Bundesliga match [against Borussia Monchengladbach]," Favre said of Reus on Friday.
"[Piszczek] has been training all week and will do that today, so we have to see if that will be enough."