The result guaranteed Bielefeld a top-two finish with three games left to play.
Bielefeld, who last played in the Bundesliga in 2009, are now on 61 points from 31 games after beating Dynamo Dresden 4-0 on Monday. They are seven clear of Hamburg SV, who have played 32 matches.
Former Bundesliga champions VfB Stuttgart are third on 52 also with three games left to play.
The top two clubs win automatic promotion while the third-placed team goes into a relegation/promotion playoff with the club that finished third from bottom in the Bundesliga.