The former France international believes the 31-year-old is the type of player who can make the difference, and hailed the ex-Barcelona and AC Milan frontman's desire to winParis Saint-Germain attacker Zlatan Ibrahimovic, and feels the Sweden international is one of the best signings of the past three decades.
The towering attacker joined PSG from AC Milan in the summer transfer window, and has quickly become a key player at the Ligue 1 giants.
"I believe he is one of the best buys in French football in the last 30 years. Zlatan is one of the best, because Zlatan is a guy who will make a difference, who will make you win or lose a trophy," Vieira told the official Ligue 1 website.
"He will be the one who will score between 25 and 30 goals. You just have to look at what he has achieved so far.
"I think he has won nine trophies in the last ten years. What I really like about Zlatan is that he is not on the field to play around; he is there because he wants to win. He is a winner."
The 31-year-old has netted 10 goals in as many Ligue 1 appearances so far.