Bologna's veteran Brazilian forward Adailton scored an equaliser deep into injury time to deny Juventus a return to the top of the Serie A table following a 1-1 draw in Turin.
The result left Juventus one point behind leaders Sampdoria, who beat champions Inter Milan 1-0 on Saturday.
Meanwhile, AC Milan's miserable start to the season continued as they needed goalkeeper Marco Storari to rescue a 0-0 draw for them at home to newly-promoted Bari.
They were booed off the San Siro pitch as they slumped to seven points behind Sampdoria after just two wins in six matches and just a solitary goal in their last five encounters.
In Turin, France forward David Trezeguet came close to a first-half hat-trick before Bologna laid siege to the Juventus goal after the break to snatch a dramatic late share of the spoils.
Juventus coach Ciro Ferrara was furious with his team.
"(The goal) wasn't Bologna's only chance, we were naive and we took too much time to get into position at the back," he said.
"On their goal no-one was there, we gave away too much. I brought in players who hadn't played for a while and maybe we had a problem gelling.
"We need to manage the ball better when we have it and be less frenetic. We need to be more balanced."
Trezeguet came close with a right-foot volley that Emiliano Viviano tipped around the post before he tapped in on 24 minutes after Jonathan Zebina's shot came back off Viviano and a defender.
The former Monaco man flashed a left foot finish just past the upright before Andrea Raggi had the ball in the net for Bologna in first half stoppage time only to be chalked off for offside.
If Juve had looked comfortable before the break, they were anything but after it with former striker Marco Di Vaio terrorising their back-line.
He escaped to bear down one-on-one against Gianluigi Buffon but put the ball wide and moments later got free again, rounded the Italy stopper only to see Giorgi Chiellini get back to clear his shot off the line.
Buffon then came to the rescue to keep out a Giacomo Tedesco shot at full stretch before Adailton thrashed the rebound over the bar.
But three minutes into stoppage time Tedesco sent a long, high cross into the box and Adailton arrived at the back post to stab a volley into the ground that bounced up and beyond Buffon's despairing dive.
Just as had been the case in their 0-0 draw at Livorno, Milan had Storari to thank for coming away with a point.
He made a string of fine saves denying Leonardo Bonucci, Honduran winger Edgar Alvarez, Emmanuel Rivas and Riccardo Meggiorini.
Argentine winger Rivas caused Milan problems and after one mazy run that saw him beat three defenders, including a nutmeg on Alessandro Nesta, he deserved a better finish than hurridly snatching at his shot and blazing over the bar.
Milan, who were largely dominated, had some good chances of their own but the best fell to the recalled Ronaldinho, whose effort looked headed for the top corner until Belgian goalkeeper Jean Francois Gillet intervened.
Italy midfielder Daniele De Rossi salvaged AS Roma coach Claudio Ranieri's unbeaten league start in charge of the giallorosso as his injury-time strike earned a 1-1 draw at Catania following Japan forward Takayuki Morimoto's opener.
Slovakian midfielder Marek Hamsik eased the pressure on former Italy coach Roberto Donadoni as his brace gave Napoli a 2-1 home win over Siena.
In other games, Serie A top scorer Antonio Di Natale continued his hot streak, netting in Udinese's 2-0 win over Genoa while Atalanta climbed off the bottom of the table with a 1-1 draw at Chievo.
Livorno, who lost 1-0 at fourth-placed Fiorentina on Saturday, are the new basement dwellers.
Source: AFP Global Edition
