Inter Milan missed the chance to go top of Serie A as they fell to a 1-0 loss at Juventus on Sunday with Francisco Conceicao scoring the decisive late goal in an action-packed match.
The Portuguese winger sparked jubilation in the stadium after 74 minutes following some clever footwork in the box by Randal Kolo Muani before he found Conceicao, who fired home.
Inter failed to capitalise on Napoli being held to a 2-2 draw at Lazio on Saturday and are two points off the pace with 54 points from 25 games. Juve are now in fourth spot with 46.
Much was at stake in the 267th Derby d'Italia, with the reigning champions knowing an away win would see them finally leapfrog Napoli, while Juve could move into the top four, having struggled to find a winning formula for much of the season.
Inter's Mehdi Taremi set the tone in an intense clash with a stunning bicycle kick that goalkeeper Michele Di Gregorio reacted swiftly to push away, before Denzel Dumfries sent the rebound over the bar.
Minutes later, Juve's Nico Gonzalez struck a powerful long-range shot that forced Yann Sommer into a fingertip save before making another stop to keep out the follow-up from Conceicao.
The chances kept coming for both sides, with Kolo Muani and Inter forward Lautaro Martinez wasting clear opportunities by sending their efforts well over the bar as halftime approached.
Just before the break, Dumfries led another Inter attack into the box but the Juve defence forced him into a tight angle and his shot clipped the post.
Both sides continued to play on the front foot in the second half as they tried to end the deadlock but it was Conceicao who finally broke Inter's resistance to delight the home fans.
Only minutes later, Juve came close to another goal as Teun Koopmeiners' shot was blocked on the line by Dumfries.
Inter pushed forward and Marcus Thuram produced a volleyed attempt but they could not find a last-ditch equaliser, leaving the thrilling title race on a knife-edge with 13 rounds to go.