The Spurs winger has been in sensational form of late, scoring 15 Premier League goals this season to alert the likes of Real Madrid and Manchester City as his current club prepares for a huge summer bidding war.
While the Wales international surged past the former England center back to score in a 3-2 victory at Old Trafford, the Red Devils stalwart says the 23-year-old must show this form for far longer to become one of the world's best.
Ferdinand Tweeted: "People mentioning Bale in the same breath as @Cristiano + Messi really don't know football! Bale been 1 of best 2 in PL this year but...He is not on CR7 + Messi's level yet...he carries on doing what he is doing for 2/3yrs then there can be a debate.
He added, "Bale showed me a clean pair of heals once this year so I'm in good position to judge! CR7 + Messi have been on another planet for 4-5yrs #consistent."
Spurs sit in third place in Andre Villas-Boas' debut season at White Hart Lane, with Bale netting two goals in the 3-2 Monday night win at West Ham - the last being a 90th minute match-winning wonder strike - leaving his side four points clear of rival Arsenal.
The Gunners travel to Spurs on Sunday, where a win for the home side would leave it seven points clear of Arsene Wenger's side in the race for Champions League qualification.