Peterson laughed off McCoy's comments, saying Tuesday in a radio interview that the Philadelphia Eagles star "didn't really mean it" when he told ESPN that he is the league's top back.
"He didn't really mean it," Peterson said during an interview with Fox Sports Radio. "If you watched his response, [he didn't mean it]."
McCoy, who led the NFL in rushing last season, responded, "Yes sir," when asked whether he was the league's best running back Monday during an interview with ESPN's "First Take."
The two-time Pro Bowler acknowledged that he is a "big fan" of Peterson's but said that the Minnesota Vikings star "automatically gets the best running back [label]" based on his reputation.
"I've got to give the young guy credit because there is nothing wrong with having confidence in yourself," Peterson said Tuesday. "But you've got to speak it with more truth. He's a heck of a running back and I like his style, so I won't get on him too much."
Peterson said he watched McCoy's interview with ESPN, claiming he laughed when the conversation about the best running back began.
"It was funny because when Stephen A. [Smith] asked him the question, he kind of hesitated, and he didn't believe it when he said it," Peterson said. "I tell the youngsters, 'Say it with your chest, like you mean it!'"
Peterson rushed for 1,266 yards -- 341 fewer than McCoy -- and 10 touchdowns last season, his seventh in the NFL. The six-time Pro Bowler made history in 2012, when he ran for 2,097 yards to fall just 8 yards shy of Eric Dickerson's single-season league record.