Romelu Lukaku scored twice and assisted another to help Inter to a 3-1 win over Lazio that lifted Antonio Conte's men above bitter rivals Milan to the top of Serie A.

Milan's shock 2-0 loss to Spezia on Saturday opened the door for Inter and they pounced at San Siro on Sunday, taking a one-point lead into next weekend's huge Derby della Madonnina.

Lazio were furious with the awarding of Inter's 22nd-minute penalty as replays appeared to show Wesley Hoedt, drafted in after Stefan Radu was injured in the warm-up, got some of the ball before taking out Lautaro Martinez.

Lukaku converted and added a second ahead of half-time with the assistance of VAR, before teeing up Martinez to seal the points after Gonzalo Escalante had given Lazio some temporary hope.

There had been little between the sides prior to the controversial penalty call, with the VAR standing by referee Michael Fabbri's decision to point to the spot for Hoedt's challenge on Martinez.

Lukaku sent Pepe Reina the wrong way to extend his perfect penalty record in Serie A to 10 from 10, and the Belgium international did not have to wait long for the landmark 300th career goal for club and country.

It had an element of fortune about it as Marcelo Brozovic slid in on Manuel Lazzari and the ball ricocheted into the striker's path, though it took a lengthy VAR check to ascertain that Lukaku was level with the last man when the initial pass was played.

Lazio had found the net in each of their past 17 league outings, however, and they kept that run going when Sergej Milinkovic-Savic's free-kick heavily deflected off substitute Escalante and beat Samir Handanovic on his 500th Serie A appearance.

But just when the visitors had some momentum on their side, Lukaku charged down the right, held off Marco Parolo and unselfishly squared the ball for Martinez to tap into an empty net.

Reina denied Lukaku a hat-trick with a good save down low but Inter, knocked out of the Coppa Italia by Juventus in midweek, retained their two-goal cushion to move to the summit.