The Brazilian joined on deadline day in a 20 million euro deal, and Alvarez believes the 28-year-old will bring qualities that will make a big difference to Walter Mazzari's side.
"He's a great player, he can play in many roles in midfield. He's someone who could make a difference in any team," he told La Gazzetta Dello Sport.
Inter faces runaway Serie A leader Juventus on Sunday looking to repeat the famous 3-1 victory in Nov. 2012 which brought the Bianconeri's 49-game unbeaten run to an end.
While Alvarez admits his side has undergone significant changes since that victory, he maintains Inter is far closer to Juventus' standard than the current 23-point gap in the Serie A standings suggests.
"I don't think so [that the gap is significant]. They've played together for three years. We have changed coaches and changed systems. We are at the beginning of a project that can give us great satisfaction," he said.
"That match [in 2012] was one of the best in recent years, but it belongs in the past. The situation is different now, although that game should serve to give us conviction. After that, it depends on us and what we do out on the pitch. It'll be a great game. Many factors affect the result. Of course, we have to leave the pitch having given everything."