Dusan Vlahovic shot Juventus temporarily top of Serie A on Saturday as the Serbia striker scored twice in a convincing 3-1 win over Lazio.
Goals in each half from Vlahovic and another in the 26th minute from strike partner Federico Chiesa at the Allianz Stadium pushed Juve a point ahead of both Milan clubs before the derby which kicks off later.
Inter Milan and AC Milan are both on a perfect nine points heading into their clash for local bragging rights, one behind Juve.
Massimiliano Allegri's Juve will concede top spot regardless of the result at the San Siro but the coach will be encouraged by what he saw in front of an enthusiastic home crowd in Turin.
Allegri has paired Vlahovic and Italy star Chiesa up front this season and the attacking duo have hit it off, combining for seven goals in unbeaten Juve's opening four matches.
Vlahovic has scored four times after a tumultuous summer dominated by rumours that he might be sold and replaced by Romelu Lukaku, now on loan from Chelsea at Roma.
Lazio, who scored through a beautiful 64th-minute Luis Alberto curler, just before Vlahovic netted his second, are 15th following their third defeat of the season.
Juve's win was a positive end to a difficult week in which star midfielder Paul Pogba was suspended for a doping violation and Leonardo Bonucci announced legal action against his former club.
Italian anti-doping authority NADO said Monday that Pogba showed elevated levels of testosterone in tests after Juve's season opener at Udinese.
World Cup winner Pogba, who has struggled with injury and risks a four-year ban, was questioned in a Paris court on Friday alongside five acquaintances and childhood friends suspected of trying to extort 13 million euros from him.
Bonucci claimed on Wednesday that Juve violated professional football's collective bargaining agreement by sidelining him over the summer before he moved to Union Berlin in Germany at the end of the transfer window.
Champions Napoli are at Genoa in Saturday's late match, trying to get back on track after falling to home defeat at the hands of Lazio last time out.