It proved a pivotal moment in an enthralling contest as Milan - inspired by Deulofeu, the game's outstanding player - never stopped attacking and deservedly halved their deficit when Alessio Romagnoli impressively stabbed home a Suso cross with just seven minutes remaining to set up the grandstand finish that the game, and indeed the occasion, merited.
The Derby della Madonnina took place in Northern Italy on Saturday morning as AC Milan played rival Inter Milan.
Pressure has been mounting on Pioli, while the mood in the Milan camp has been one of positivity following six victories in their last nine and the long-awaited completion of the €740million takeover by Chinese investors this week.
Inter, which is also owned by a Chinese group, was taken over past year by Suning. "A win would have been better today but a draw which arrived in this way and for how the team played is a good start".
"Our first half hour was good, we created chances, but we weren't clinical enough".
"In the dressing room we had chose to push after the restart to finish the game, but we weren't able to make it 3-0".
Deulofeu went close again in the 14th but his effort went off the base of the right post from a tight angle.
Antonio Candreva had given Inter the lead, with striker Mauro Icardi proceeding to make it 2-0.
The two combined wonderfully well all afternoon and really should have produced another goal 10 minutes into the second half when Icardi found Perisic with a perfectly-weighted ball across the Milan box only for the Croatian to shoot tamely at Donnarumma.
Inter have substantially underachieved this season while AC Milan are exceeding expectations, says former Italy global Massimo Oddo.
Balotelli is now at Nice, for whom he has scored 13 league goals in 19 appearances this season.
Milan then pushed for an equaliser, but with 96 minutes on the clock it looked as though it wasn't going to come before experienced Colombian defender Cristian Zapata latched on to a cross and forced the ball over the line.
Elsewhere, Cagliari beat Chievo Verona 4-0, Torino drew 1-1 against Crotone and Bologna's match at Palermo ended 0-0.