That followed his assertion that Ferguson's move in bringing veteran United midfielder Paul Scholes out of retirement during the January transfer window was a sign of desperation.
France World Cup winner Vieira is now the football development executive at United's local and English Premier League title rivals Manchester City.
United manager Ferguson responded to Vieira's comments about Scholes by saying that if the City man wanted to play mind games he had "plenty of ammunition" to throw his way.
Ferguson, as good as his word, said City manager Roberto Mancini was "desperate" in recalling Carlos Tevez for the title run-in, despite the Argentina striker's self-imposed several-month long exile after a row with the Italian.
However, an undaunted Vieira went on the offensive again Wednesday, a day after referee Michael Oliver refused to give Fulham what many observers thought was a penalty in a 1-0 league defeat at United's Old Trafford home on Tuesday.
Victory left leaders and reigning champions United three points clear at the top of the table, with eight league games of the season left.
"When United play at home they get some advantage that other teams don't get," Vieira, who made his name in England as an outstanding defensive midfielder with Arsenal, told BBC Sport.
"When you go to United, Madrid, Barcelona or Milan, it's always difficult for the referee to go against these kind of teams.
"This is the way it is. It's something the teams who are used to winning get all the time, so we need to win games so we have this advantage in the future."
City were last crowned champions of England back in 1968 but Vieira, speaking at the Soccerex conference in Manchester, insisted: "This is our moment. Since the start of the season we've been the best team and played the best football.
"I believe the club deserves it (the title)," the 35-year-old added.
However, Vieira -- who won three Premier League title with Arsenal, conceded: "When you are first you have the advantage, they are favourites.
"It's important not to lose focus, so many things can happen. People try to build this fire between the clubs. The heat is going to get more and more."
Vieira's comments drew a quick response from Unite centre-back Rio Ferdinand on Twitter.
"Why is Viera so concerned with Man Utd....2 comments in a week or so....c'mon maaaaaan let it go," said the England international.
Source: AFP
Source: AFP