Manchester City's manager Roberto Mancini is confident Mario Balotelli will be unaffected when Porto return for the second leg of the Europa League tie on Wednesday after racist chants were aimed at the forward in their 2-1 win against the Portuguese champions last week.

The Italian and his team-mate, Yaya Touré, had what sounded like monkey noises aimed at them during the first half, with Balotelli's substitution in the second period being greeted with similar sounds. Uefa confirmed on Tuesday night that it has opened disciplinary proceedings against Porto after City made an official complaint to Uefa.

While Uefa is now considering whether Porto have a case to answer, around 1,200 of their supporters are expected to travel to the Etihad for the return leg. "What happened can happen sometimes in Italy or France, but Mario is strong," Mancini said. "I don't know what's happened because I was concentrating on the game. I didn't hear this but everywhere there are some not clever people. This is life."

Mancini said City were as determined to win the Europa League as the Premier League. He said: "In Europe there are two competitions – the Europa League and the Champions League. We played in the Champions League for the first time this year and we were really unlucky not to go to the second stage with 10 points. If we win the Europa League it would be an important moment for the club.

"It won't be easy because there are top squads, but we want to arrive in the final, it's important for us. We want to win the Premier League also. We want to win [everything], we are here for this. We are on the top and we have 13 games. If we win the next 12 games we will win the Premier League."

An own goal from Alvaro Pereira and a winner from Sergio Agüero make City favourites to progress to the last 16 and Mancini said: "I'm very pleased about the game in Porto. In the first half we played a good game because we left only a few chances to Porto and we had three or four chances to score. In the second half we played higher and better.

"Every game is dangerous but it is better to start from 2-1. We know that Porto is a top team and we should play like it's 0-0. It is a difficult game and will depend on us – we need to play well. For us every game is serious, we want to win all the games, sometimes it's possible sometimes not. But for us it's a serious competition."

Mancini signed David Pizarro on loan from Roma in January and the manager said the Chilean midfielder will have a role to play this season. "David is OK. He played his last game at the end of November. He is maybe not 100% and needs to work but maybe he can play the next game. We have 13 Premier League games and another seven or eight games in the Europe League if we get to the final. He has experience and quality so can be an important player."

Manchester City (probable: 4-2-3-1) Hart; Richards, Kompany, Lescott, Clichy; De Jong, Barry; Nasri, Y Touré, Silva; Balotelli.

Porto (probable: 4-3-3) Helton; Sapunaru, Otamendi, Rolando, A Sandro; Fernando, Moutinho, Lucho; J Rodríguez, Hulk, Varela.