AC Milan produced their best performance of the season to secure a 1-0 win over Juventus thanks to a first-half penalty from Robinho which handed the champions only their second defeat of the campaign.
Milan suffered a scare when 'keeper and captain Christian Abbiati was forced off with a back injury from the warm-up and was replaced by Marco Amelia.
But two days after club owner Silvio Berlusconi had visited their training ground for a serious talk with the players, the Rossoneri put the setback behind them to produce a committed display that limited Juve's chances.
Right back Mattia De Sciglio gave Milan hope in the fifth minute when he danced past Andrea Pirlo then Kwadwo Asamoah to hit an angled shot which forced Gianluigi Buffon to save with his fingertips.
When Kevin Prince Boateng found space and put Robinho through on 10 minutes Juve were quick to spring the off-side trap.
Milan then launched a promising attack after Arturo Vidal's shot had been blocked, with Robinho carrying the ball upfield and laying off for Boateng, whose effort was blocked by Buffon.
Almost to a man, Milan were putting in the extra yard to shut down Juve, whose best chance of the opening period came when Fabio Quagliarella turned and shot from 20 metres only for Amelia to collect easily.
A Stephan El Shaarawy shot was then blocked as he wound up from 20 metres and on the half-hour the 20-year-old striker hit a weak effort that Buffon caught.
A minute later a handball in the area by Chilean Mauricio Isla as El Shaarawy rose for a cross gave the hosts the breakthrough.
The referee pointed to the spot and although Buffon did well to get his hand to Robinho's spot-kick he could not stop it hitting the back of the net.
Juve were being given few chances to go forward, and when Isla found space on the right of the area his skied ball when he intended to cross underlined their frustrations.
At the end of the half Milan were on the attack again, Robinho jumping on to Vidal's wayward pass to set up El Shaarawy to the right of goal, only for the striker to send his shot wayward from a tough angle.
Juve began the second half in more positive fashion and had Milan on the ropes for spells but were often left frustrated with the end product.
Juve assistant coach Angelo Alessio replaced Quagliarella with Sebastian Giovinco in the 57th minute and Juve came close to levelling.
Pirlo's header back into the area following a poor clearance found striker Mirko Vucinic close in but his shot went well over the bar and then Vidal's effort from the right was caught easily by Amelia.
Juve were beginning to threaten and when Vidal's cross from the right found Giovinco unmarked in front of goal the little striker's bicycle kick went wide of Amelia's upright.
Milan coach Massimiliano Allegri replaced Robinho with Pazzini but following another interception El Shaarawy powered down the left on 75 minutes but saw his cross for Pazzini bundled out for a corner.
In the closing period Juve kept the pressure on and Milan survived a huge scare when Constant blocked Vucinic's shot from Giovinco's pass.
A minute later Vucinic's strike forced Amelia to parry the ball for a corner, from which the keeper was forced into a two-fisted save which frayed Milan nerves.
Juve kept pressing and had claims for a penalty in the dying minutes when Giovinco, clear on goal, was hauled down by Amelia. However the 'Atomic Ant' had already been ruled offside.