The Brazil international believes the return of the Blaugrana star can aid the club in their pursuit of Liga and Champions League success this season
The Spanish giants were heading for a Champions League exit against Paris Saint-Germain a fortnight ago before Messi came off the bench and proved instrumental in Tito Vilanova's side progressing to the semi-finals.
The Argentina international has missed the Blaugrana's last three Liga games, however, but has been included in the squad to face Bayern Munich on Tuesday night and Alves made no attempts in playing down his importance to the cause.
"Messi knows he is the best player in the world and the power he has to change a game around just with his presence out on the pitch," the Brazilian full-back told AS.
"We needed him against Paris Saint-Germain and sometimes you have to find extra reserves or strength for the benefit of the team.
"Messi's presence changes a lot of things. It frightens our rivals and excites our fans... that is because we are talking about the best, because he has magical powers."
The Brazil international also believes his team-mate's talent is natural compared to Real Madrid star Cristiano Ronaldo, whose ability he believes comes from his effort on the training field.
"Messi has an innate talent and Cristiano's comes from hard work, that's the difference. Messi was born with a gift which has allowed him to become the best and he is, he didn't have to work at it, he was born with it," added Alves.
"Cristiano is very good but he has worked to improve and be the best. Messi, on the other hand, works normally and is the best because he has been given a gift by God. That's just my own, humble opinion anyway."