Romelu Lukaku scored two and created the other for Lautaro Martinez, as although Lazio had more possession, Inter won 3-1 to leapfrog Milan at the top of the table.
With Milan and Juventus losing on Saturday, the Nerazzurri knew a victory would put them in first place, but the Biancocelesti were coming off six consecutive Serie A victories and pushing for joint third place.
Arturo Vidal was the only absentee for the hosts, so Christian Eriksen started on his birthday. Luiz Felipe and Thomas Strakosha missed out for Lazio, with Stefan Radu pulling out in the warm-up, replaced by Wesley Hoedt.
To mark Chinese New Year, Inter players had their names written in Chinese characters on the back of their jerseys.
Eriksen set up two good opportunities for Marcelo Brozovic and Lautaro Martinez, but both were blocked by defensive interceptions, while Samir Handanovic came flying outside the area to clear from Joaquin Correa.
Romelu Lukaku knocked it on for Lautaro Martinez and Hoedt dived in with a mistimed sliding tackle, as he got some of the ball, but probably not enough. Lukaku sent Pepe Reina the wrong way to convert the spot-kick.
Milan Skriniar avoided a similar fate with a crucial tackle to stop Correa going clear, as Lazio continued to have more of the ball and Handanovic made a one-handed save on Ciro Immobile’s daisy-cutter.
However, it was Inter who were more direct on the counter-attack, despite being the home side, as Reina had to smother at Lautaro’s feet on another Eriksen assist and then smother a Lukaku snapshot.
VAR was involved again for the second Inter goal, which was initially disallowed for offside. Brozovic’s sliding tackle ricocheted off Manuel Lazzari’s shin and into the path of Lukaku to score. It was not an intentional pass. However, when Brozovic made the initial touch, Lukaku was level and therefore Lazzari’s contribution was irrelevant.
Simone Inzaghi made a double change at the break and his team continued to dominate possession without real shots on target, as Marusic and Francesco Acerbi fired over from very promising opportunities.
Once again, a lucky ricochet fell kindly for Inter and Lautaro Martinez sent Achraf Hakimi clear, but substitute and makeshift defender Marco Parolo made a desperate interception as he was pulling the trigger.
Moments later, Lazzari was brought down just outside the area by Hakimi and on that Milinkovic-Savic free kick, it took a big deflection off Gonzalo Escalante to wrong-foot Handanovic. Initially, the goal had been awarded to Escalante, but the Lega Serie A changed it to the Serbian, as his effort had originally been on target.
It was game on and Lazio were pouring forward, but this left them open to the counter-attack. Lukaku deserves most of the credit for the goal, as he started the run from his own half, held off Parolo while sprinting, kept his cool and rolled it across for Lautaro Martinez to tap into an empty net.
It was end-to-end stuff, Reina using his legs to parry a Lukaku angled drive, Vedat Muriqi’s shot charged down and a header straight at Handanovic.
Felipe Caicedo also nodded off target from Patric’s cross, but Lazio couldn’t make the pressure count.
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