Blatter said three years of experimentation failed to come up with technology that was 100 percent accurate.
Cottbus keeper Gerhard Tremmel dived to parry Marco Russ's shot. The ball hit the post and bounced back to Tremmel, and Referee Michael Kemptner awarded a goal. But TV replays didn't reveal that the whole ball crossed the line.
The loss is severe for Cottbus, which is near the relegation zone.