Mauro Icardi completed a superb hat-trick from the penalty spot in the final minute as Inter snatched a pulsating 3-2 win over AC Milan in the Derby della Madonnina.
Luciano Spalletti's team remain unbeaten this season and move above champions Juventus up to second in the Serie A table but they were made to fight hard by their neighbours after half-time at San Siro.
Icardi's instinctive finish from Antonio Candreva's pinpoint 28th-minute cross preceded a passage of play before the interval when a Milan side still bedding in after their frantic close season in the transfer market appeared increasingly overmatched.
But Vincenzo Montella's decision to bring teenage forward Patrick Cutrone on for Franck Kessie at the break proved inspired and the Rossoneri were level when Suso stylishly picked out the bottom corner from long range.
Inter unexpectedly found themselves on the ropes and were indebted to Samir Handanovic's stunning reaction save from Giacomo Bonaventura before Icardi started and ended a 63rd-minute counter-attack, crowning it with a brilliant volley.
Milan's head coach is likely to face more speculation over his future after a fourth defeat in eight Serie A matches but his team's spirit could not be called into question in the 81st minute when Bonaventura turned the tables on Handanovic – the goalkeeper fumbling over the line to be credited with the own goal.
There would be a further twist when Ricardo Rodriguez was adjudged to have impeded Icardi at a corner and the Argentina striker proved to be the coolest man in a stadium ramped up to fever pitch.