UEFA president Platini was a strong supporter of Blatter's in the past but believes it was wrong of the 78-year-old to go back on his word to stand down in 2011.
Speaking in Sao Paulo ahead of last night's opening match, Platini said: "I do not support him. I have known him for a long time and I like him but I am not in favour of him having a new term [FIFA delegates defeated moves to bring in term limits and age limits for officials, effectively clearing the way for Blatter to stand for re-election].
"I supported him in 1998 but I do not support him in 2014. And in the future I will not support Mr Blatter. I told him. I think that FIFA needs a breath of fresh air. In 2011 he asked for our support [UEFA's] and told us that that would be his last term."
Platini said it was still a possibility that he would run against Blatter but he would not decide until the end of August. "It is an option," he added. "But it is not because Blatter is running that Platini will not run. And it is not because Blatter is not running that Platini will run. My only concern is knowing what I want to do. I am 60 soon and need to know what I want. I will take my time."
"It is not just mine [the decision to stand for the FIFA position] but also that of my family, my children. But choosing between UEFA and FIFA is not choosing between going to hospital or going to prison - the choice is not a negative one. But when I launch, it is to win."
Stewart Regan, the Scottish FA chief executive, last night backed Platini's stance. "UEFA members gave their support to Mr Blatter in 2011 on the proviso that this would be his last term in office. The goalposts have now been moved. In 2011, UEFA members made it clear that we believed that a change of leadership was needed at the end of Mr Blatter's current term. The Scottish FA continues to hold that belief.
"The Scottish FA was one of a small number of, mainly European, associations that voted in favour of proposals to impose an age limit and maximum number of terms on FIFA presidents. The proposals were rejected by the majority of members. UEFA must now consider whether to put forward a candidate for the FIFA presidential elections in 2015."