The Brazilian was thrilled to see his side bounce back from defeat to Valencia by beating Real Sociedad, but Xavi was quick to praise Real Madrid for its own victory.
A strike from Sergio Busquets and an own goal from Enaut Zubikarai secured a first-leg win for the Catalans in the Copa del Rey semifinal as they moved to put their weekend defeat to Valencia firmly behind them.
Alves claimed Camp Nou "can feel like an away ground" following the supporter reaction to the loss on Saturday and the Brazil international believes it would be best for fans to keep their negativity away from matches.
"Fans are very pessimistic when there is a bad result," he said after the win on Wednesday. "Those who don't come to the ground are not true cules. Everyone has to do their part. If you doubt this team it's better that you don't come.
"It's important to win because we live like that. When you have a bad result against Valencia, some doubts are normal. What we cannot do is doubt ourselves.
"We have to continue working because in the end we want to enjoy ourselves with the fans."
Alves added the importance of keeping a clean sheet in the first leg and paid tribute to goalkeeper Jose Pinto for keeping the visitors at bay.
"When you're concentrating you do things well. I'm really happy for Pinto because he helped us keep a clean sheet," he added. "It was important not to concede and we managed that. We will have to go there to get to the final."
Inigo Martinez was shown a straight red card for dissent following Busquets' opener, but Barca midfielder Xavi admits he is unsure what the Sociedad man said to the officials that prompted his dismissal.
"We'll see the report. I don't know what Inigo said to the referee," he told Antena 3.
Real Madrid beat rival Atletico Madrid 3-0 in the other semifinal and Xavi believes both sides can be happy with their first-leg performances.
"They had chances in the first half but we had lots of opportunities and we didn't take them.
"They had a very favorable result, much like ours. Madrid were outstanding, clearly."