Marco Di Vaio struck a brace as Bologna shocked Juventus 2-0 at the Stadio Olimpico di Torino.
Sitting in seventh in the Serie A standings, Juventus continued their inconsistent form when they dropped points at home courtesy of two second-half goals to their former striker.
Vincenzo Iaquinta had the best opportunity in the first half and was unlucky not to have put the hosts ahead on the stroke of half-time when his shot came back off the post.
The visitors took the lead moments after the re-start when Di Vaio slotted home, before the Italian striker beat the challenge of two markers and buried the ball home for his second goal of the night in the 66th minute.
Luca Toni's late effort for Juventus was cleared off the line, a sign of the luck that Luigi Delneri's side are not getting this season.