Palermo stunned AC Milan 1-0 to end a run of five straight defeats and blow the Serie A title race wide open.
Romania centre-back Dorin Goian was the unlikely hero scoring the only goal of the game yesterday that could result in Milan's lead being cut.
The rossoneri came into the game five points clear of champions and city rivals Inter Milan, who play Lecce on Sunday, while Napoli could also reduce their arrears to three-points if they beat Cagliari.
Palermo's win also improved their hopes of securing European football next season.
Palermo were off to a great start as they took the lead after just 10 minutes from a corner.
Ezequiel Munoz rose at the back post to head the ball back across goal where Giulio Migliaccio nodded it into the middle and the unmarked Goian had time to control the ball, turn and volley home.
Milan's response was almost immediate as a Clarence Seedorf corner somehow flashed across the face of the six-yard box with Alessandro Nesta sliding in a fraction too late to turn it in at the back stick.
Palermo in general enjoyed the better chances and Javier Pastore played a one-two with Mauricio Pinilla before rifling just off target.
A Pastore back-flick then gave Pinilla a chance but Christian Abbiati got down low to his right to save.
Cassano had a chance on the break but fired wildly off target before Palermo goalkeeper Salvatore Sirigu came out quickly to save at Pato's feet.
Palermo played on the counter attack in the second half but wasted several glorious chances to stretch their advantage.
Pastore spurned the first two with a poor pass and then bad decision-making but when he later squared the ball across the six-yard box, Matteo Darmian put it wide on the slide.
Milan nearly made them pay on 65 minutes as substitute Robinho found space in the box and crossed for Mathieu Flamini, whose goalbound shot was punched away by Sirigu.