Sir Alex Ferguson's side opened up a seven-point lead over their nearest rivals Liverpool at the weekend as they beat Blackburn 2-1 while Liverpool were held at home by Manchester City.
But speaking as the team flew out to Italy for Tuesday's Champions League clash with Inter Milan, club legend Robson insisted the United players cannot afford to believe that the title race is over.
"I don't think it's decided, not at this moment in time," he told Sky Sports News.
"There's still a long way to go in the season and nobody at the club will get carried away because of the lead that the lads have got at the moment.
"But I think what it does do is make the weekend of the Liverpool game a very big one. If United actually win that game than that is going to be a big step towards winning the title."
Four moreUnited have plenty to think about before that fixture on March 14 as they continue their bid to win four more trophies by the end of the season.
They will be hoping to claim the first of those in the Carling Cup Final at Wembley next Sunday and Robson feels the current squad has what it takes to make history.
He continued: "If United get that little bit of fortune on their side then the Champions League, the FA Cup and the Carling Cup - they are already in the final of that - are all a possibility.
"But you do need a bit of fortune on your side."
Before their Wembley date comes a showdown with Jose Mourinho's Inter Milan in the last 16 of the Champions League and Robson refuses to underestimate the size of the task ahead.
He said: "You've got to give a team plenty of respect if they're nine points clear in Serie A.
"Jose's done a good job there and they've got some really good players.
"But United have got nothing to fear because they're flying at the moment. The lads are full of confidence."