Romelu Lukaku came off the bench to give Internazionale a crucial first-leg lead over Porto in their bid to reach the Champions League quarter-finals. The Belgium international struck with four minutes remaining to secure a 1-0 victory at San Siro after the visitors had seen midfielder Otavio sent off for a second bookable offence. In a tight first half, Inter striker Lautaro Martínez might have done better with an early header and Porto keeper Diogo Costa had to tip over Hakan Calhanoglu’s audacious attempt from an improbable angle. However, the visitors grew into the game and threatened when Marko Grujic forced a 37th-minute save from goalkeeper Andre Onana before Galeno headed the rebound wide, leaving the sides locked together at the break. Nicolo Barella went close to the opening goal for the home side when he volleyed just wide after running on to Milan Skriniar’s raking 52nd-minute pass, but Onana had to save from Mehdi Taremi twice and Zaidu as the Portuguese side responded. Barella only just missed the target once again with 21 minutes remaining, before Otavio was shown a second yellow 12 minutes from time. Lukaku finally made the breakthrough to give Inter a slim advantage to defend in Portugal.