Leicester City manager Craig Shakespeare said he “has never had any falling-out” with former manager Claudio Ranieri.
Ranieri was sacked by the Premier League champions in February and said on Monday night that “someone behind” him may have been working against him.
Shakespeare said: “We have never had any arguments or hard feelings.
“Free speech is there for everybody. I don’t have any problem with that. I have a clear conscience.”
Leicester won their first five league games under Shakespeare before losing at Everton on Sunday but start as underdogs against an Atletico side who have reached the Champions League final in two of the past three seasons.