Inter Milan stormed to the Serie A summit thanks to a second-half fightback that clinched Antonio Conte's men a 4-2 Derby della Madonnina victory over AC Milan.
Captain Marcelo Brozovic, Matias Vecino, Stefan De Vrij and Romelu Lukaku all found the net as Inter rallied from a 2-0 half-time deficit to stun the Rossoneri and capitalise on a rare Juventus slip at Hellas Verona.
Juve's grip on the Scudetto has long been confirmed as vice-like, given the Old Lady have lifted the shield eight times on the trot.
But Inter are asserting themselves as genuine title contenders and did so again on Sunday night in some style, having been two goals down and listless at the break.
Warhorse striker Zlatan Ibrahimovic teed up Ante Rebic then headed home himself to hand Milan a stranglehold at the interval, with Inter staring down the barrel of failing to take advantage of Juve's 2-1 loss in Verona on Saturday.
Two goals in three minutes after the turnaround changed everything though, and when Holland defender De Vrij headed in the third, Inter were en route to the top of the table – overhauling Juve on goal difference.
Milan fired several warning shots of their intent from the off, and Inter failed to heed any of the threats.
Hakan Calhanoglu drove against a post from 20 yards in the most glaring of them all.
And Milan's dominance was justly rewarded when Ibrahimovic nodded down into Rebic's path and the Croatia midfielder tapped home.
Six minutes later Milan wrestled full control, with powerhouse striker Ibrahimovic heading in the second.
As the teams left the field at the break it was hosts Inter who trudged off stunned then, with Milan dominant at San Siro come the interval.
Conte clearly used half-time to maximum effect though, because when play resumed this was a match transformed.
Suddenly Inter boasted the bite and tenacity that had been sorely lacking from their callow first-half showing.
And the home side needed precious little time to fight back onto equal terms.
First, captain Brozovic connected sweetly on the volley from the edge of the area, to halve Inter's arrears.
And then Vecino buried his first-time effort on the run, after Sanchez had raced onto a through ball, spun back and threaded back across the box to the Uruguay midfielder.
Two goals in three minutes, and Inter were level – with more than half an hour to hunt down a winner that would have catapulted them to the top of the table.
And when Antonio Candreva whipped in a threatening corner, De Vrij stooped to deliver a looping header to complete a remarkable Inter comeback.
Milan pushed for a leveller late on, and Ibrahimovic hit a post with a towering header.
But in stoppage time Lukaku thumped in a header at the other end, to finish the argument entirely, and send Inter top of the pile.
Lukaku started the move, rolling his defender before laying off a lovely wide ball, before nodding into the net in style.
The former Manchester United hitman was booked for removing his shirt in celebration, but cared little for the yellow card, continuing to clench his raised fist as the punishment was delivered.
