Substitute Romelu Lukaku scored the only goal as Inter Milan beat 10-man Porto in the first leg of their Champions League last-16 tie.
Lukaku converted a rebound after his first effort had bounced off the post in the 86th minute at the San Siro.
Porto had a double chance at 0-0 but Inter goalkeeper Andre Onana denied both Zaidu Sanusi and Mehdi Taremi.
The visitors had Otavio sent off in the 78th minute for two bookable offences and conceded eight minutes later.
The second leg takes place at Porto’s Estadio do Dragao on Tuesday, 14 March.