Ceferin, little-known outside his native Slovenia until three months ago, swept to a resounding win on Wednesday, picking up 42 of the 55 votes cast by UEFA's member associations.
The other 13 went to his only rival, experienced Dutch administrator Michael van Praag.
"Mr Ceferin has said it as well, this is imagination and lies and I think the result speaks for itself," former UEFA general secretary Infantino told reporters.
"It's an insult to the intelligence of the 55 associations who go and vote...convinced by a programme."
In July, world soccer's ruling body FIFA denied a report in the Dutch newspaper De Volkskrant that Infantino was interfering in UEFA's election.
However, the allegations have continued to gather momentum and a report by the Norwegian website Josimar last week, which made similar claims, led to a brief spat between the two candidates.
Van Praag said in a tweet that he was "shocked" to read the story and that UEFA was back to its old way of doing business.
Ceferin, elected president of Slovenia's football federation in 2011, replied that his rival was trying to pollute the campaign.
Infantino said Wednesday's voters were looking for a fresh approach from the replacement for Michel Platini who had governed UEFA since 2007 and been re-elected twice until he was banned by FIFA in October for ethics violations.
"It was a very convincing success," explained Infantino. "He has some very good ideas, he is a new face for many but he is a very competent person, head of a national association.
"I think the associations who voted have sent a clear message they wanted somebody new. This is the democracy, it was an important success because also with the numbers it gives him the legitimacy to do the reforms."
(Editing by Tony Jimenez)
