Ezequiel Schelotto scored his first goal for Inter Milan only three minutes after coming off the bench to earn his side a 1-1 draw with city rivals AC Milan at the San Siro.
Inter were giving a pounding in the first half, but somehow traipsed off at half-time trailing only 1-0 after Stephan El Shaarawy's opportunistic finish on 21 minutes looked like handing Massimiliano Allegri's side their first derby success in almost two years.
Inter made the most of their good fortune with a much more organised display in the second period and equalised on 71 minutes when new winger Schelotto - barely on the park to take over from Esteban Cambiasso - rose to glance a header into the corner of the net from Yuto Nagatomo's pinpoint ball.
The result means it is as you were at the top of Serie A with third-placed Milan a point ahead of Lazio and Inter, but second-placed Napoli will move nine points clear of Milan in the race for a Champions League spot if they can overcome Udinese on Monday evening.
Milan enjoyed a rousing 2-0 win over Barcelona in the first leg of their Champions League last-16 tie in midweek, and built on that with a commanding first-half performance in front of 80,000 fans.
Booed by the Inter fans, former Manchester City forward Mario Balotelli must be scratching his head wondering why he never scored at least two goals against his old club.
Robinho, Mathieu Flamini, Daniele Bonera and Nigel De Jong were all injured for Milan, but Antonio Nocerino started and so did Balotelli, who was cup-tied for the win over Barcelona.
Alvaro Pereira was banned for Inter while Diego Milito, Matias Silvestre, Walter Samuel, Gaby Mudingayi, Joel Obi and Luca Castellazzi were all injured. Andrea Ranocchia passed a late fitness test after damaging his knee against Cluj in a 3-0 Europa League win on Thursday while Ricky Alvarez was also in from the start.
Milan moved ahead after a sustained period of pressure when El Shaarawy raced onto Kevin-Prince Boateng's pass to slide the ball high into the net from 12 yards out with the outside of his right boot.
It was a finish of real beauty and only the excellence of Inter goalkeeper Samir Handanovic would deny Milan the second goal their play merited.
Handanovic somehow managed to claw out Balotelli's bullet header on 28 minutes from El Shaarawy's corner.
The Inter goalkeeper would then do likewise to halt a Balotelli toe poke from the superb Mattia De Sciglio's cross into the heart of the Milan area a minute later.
Balotelli was left kicking a post in frustration. It was little wonder as the Inter goal continued to lead a charmed life.
Balotelli was again left frustrated when Handanovic dived low to his right to repel a powerful effort from a Balotelli free-kick from distance that fairly dipped and swerved at the target from over 30 yards out minutes before half-time.
Andrea Stramaccioni's Inter were transformed in the second half as they managed to take the bite out of Milan's attacks while getting forward with some purpose.
Milan goalkeeper Christian Abbiati made his first notable save of the night on 54 minutes when he halted Rodrigo Palacio's shot from Cambiasso's cross with an agile diving stop that was the equal of Handanovic in the opposing goal.
Handanovic was more of a spectator in the second half as Milan seemed to run out of steam, but was needed to make a brave block in denying Balotelli before Schelotto - signed on transfer deadline day last month from Atalanta - found the equaliser.
It was the first time the Milan derby had ended in a draw since October 2004, a sequence stretching back over 16 fixtures, but Milan's fans will feel hard done by.