Martin O'Neill has described as laughable and unfair the decision to play the final Old Firm derby of the season three days after Celtic's Uefa Cup semi-final second leg in Portugal.
Rangers will host Celtic in a crucial league meeting on 27 April
Strathclyde Police on Friday publicly backed the decision made the previous day by a majority vote of the Scottish Premier League's 12 clubs.
But team boss O'Neill views it as a slap in the face for Celtic considering his side have done so much this season to improve the perception of the league worlwide.
The SPL and police want to avoid the scenes of violence that followed the Old Firm match in 1999, when Rangers clinched the title on the season's final day.
The league chose to play this season's final Old Firm match on the first weekend after the league split, 27 April, as any date after that would be arithmetically possible to produce a league decider.
But O'Neill said: "Fortunately, it has not happened recently, but there is always the possibility of something happening after an Old Firm game, no matter when you play it.
Perhaps the SPL should fine themselves for unsporting behaviour
Celtic manager Martin O'Neill
"Historically speaking, it has never been the first game after the split."
He admitted that, in recent seasons, the league title had been decided long before the split took place and therefore negated such talk.
"For the SPL's sake, you want it to be exciting and it has been exciting," said O'Neill.
"But the SPL admit themselves that this is the most unsporting date.
"We have reached the semi-finals of the Uefa Cup and the SPL have even got a bit of credit for it. Then they do something like that.
"Perhaps the SPL should fine themselves for unsporting behaviour.
"I am just glad they did not make it Friday morning after we come back from Portugal.
"It is laughable and I am sure even Rangers will be embarrassed by the decision."
Rangers, eight points clear of Celtic but having played two more games, have attempted to distance themselves from the row and manager Alex McLeish refused to comment on Friday.
Rangers' Alex McLeish refused to comment about the decision
SPL chairman Lex Gold described as "garbage" suggestions of bias and that the decision would have been different had Rangers been in Celtic's position.
Celtic chief executive Ian McLeod has threatened to take the matter all the way to the Scottish Executive, but Gold did not think there was any point in an appeal against a decision that led to six votes for, three against, with three abstentions.
Strathclyde Police also defended a decision on which it had been consulted.
A statement said: "Following events on the 2 May 1999, it was decided that Old Firm matches would be rearranged if there was a possibility the SPL could be won on that day.
"This was taken to ensure public safety.
"The SPL has calculated that the only date Rangers can play Celtic without deciding the league's outcome is Sunday 27 April. Strathclyde Police fully support this decision."