Ally McCoist believes Rangers are four "top, top" players away from challenging Celtic.
Announcing a five per cent hike in season tickets on Monday morning, Gers chairman Dave King claimed the Ibrox club are "within tangible reach" of becoming the dominant force in Scottish football.
However, Old Firm rivals Celtic are on the cusp of an unprecedented domestic treble treble with an eighth successive Ladbrokes Premiership title all but secured as they sit 11 points clear of Steven Gerrard's Rangers with five fixtures remaining.
Former Gers striker McCoist managed the Light Blues between 2011 and 2014.
He was speaking at The Emmie Smillie Charity Foundation event at which they donated £300,000 spread across five charities – Kilbryde Hospice, Beatson Cancer, St Andrew's Hospice, St Margaret's Hospice, The Prince and Princess of Wales Hospice and Marie Curie – and he responded to King's claim.
"How do you define tangible reach?," said the 56-year-old.
"There has definitely been an improvement, there is no doubt about that.
"But Celtic still look the better team by a bit.
"That said, Rangers won the Old Firm game before last and probably should have got something with 10 men last time (2-1 win for Celtic) but you just feel that if it came to the crunch that Celtic would have a wee bit too much for them.
"Fans to a certain degree, don't want to be within reach, they want to be alongside Celtic, serious about challenging at the top of the league, winning cups, and it is going to take certainly four players for them to do that.
"Rangers need to get four top, top players who are going to go into the team and play.
"And I might be changing my mind on that if you are selling a couple.
"Whether they take the money for Alfredo Morelos, take the money for James Tavernier and reinvest it but I think they are three or four players away.
"And Steve and Gary (McAllister, assistant) are intelligent men, they will know that.
"If you want to win titles then you have to have a vastly improved level of consistency.
"The next step for Rangers is definitely cup finals and a sustained title challenge.
"It is a massive summer for Rangers and it will be a big summer for Celtic as well.
"You don't know who the manager is going to be, I don't know if Neil Lennon is going to get the job (permanently) and there is certainly going to be changes in playing staff."