Genoa won 2-0 thanks to goals from Andrea Pinamonti and Maxwel Cornet.
Vieira said afterwards: "It was a very important match. Getting the three points was our goal. We took a step forward but there are still many points to take. The thing I liked tonight is that we managed the difficult moments well.
"We were under pressure but we remained calm and organized. Those who came in brought a bit of quality and energy. In the end I think this was a team victory. The MVP was the team.
"It was a game where they could have scored one or two goals. We had the chances to score but it was a difficult game. We remained calm in the difficult moments and the management was done very well."
On Cornet, Vieira added: "He's not at his best yet, he did a great job. I'm very happy. He lost a few balls that he shouldn't lose, this means we have things we need to work on but he's a quality player."