The Argentina international joined the North-East club on a temporary basis from Inter Milan on deadline day.
Alvarez, 26, was heavily linked with a switch to Arsenal prior to joining the Nerazzurri, and Poyet is excited about what his fellow South American will offer his side.
"Ricky is an exciting player to watch," he told reporters. "He is technically gifted and can do things with the ball that the rest maybe cannot with that last pass, assist or option.
"Sometimes when a team drops deep it becomes difficult to break them down but he has the ability to break those lines and give us something special.
"Ricky will play well, maintain possession and if we make sure he gets the ball in the right area he will be great to watch because he will do so many things."
Alvarez is expected to make his club debut in Saturday's visit of Tottenham Hotspur.