"They'd be using white bats all game, and then all of a sudden, a black bat comes out," Posada said. "There are a lot of things that you saw. Standing in one area, and all of a sudden Mariano comes in, and you're a little further out.
"A left-handed hitter would get off of the plate a little bit more so the cutter wouldn't be on his hands. There are a lot of things that they did; adjustments that told me that they were beaten."
On an afternoon when the Yankees honored Rivera's long and illustrious career, few could offer a better perspective than Posada, a member of the "Core Four" who was behind the plate for 293 of Rivera's 652 career saves, more than any other catcher.
What was even more impressive to Posada than the mind games Rivera played on opponents, however, was Rivera's own mental strength and positive demeanor after the most crushing defeats.
"Mariano, when he was done talking to the media, he was done with it," Posada said. "And why was he like that? He told me that he gave it all out on the field, and he wouldn't change anything that he did about it.
"They just happen sometimes; they're going to get you. [The] 2001 [World Series] was probably the toughest one, but after he talked to the media, he was good with it. He knew that he was going to get another chance."
That rock-solid perspective, Yankees manager Joe Girardi said, is what he has grown to appreciate the most about Rivera.
"I think you can throw out the statistics. I think it's the way he does his job," Girardi said. "I said that about Mo earlier today: baseball is not who he is. Baseball is what he does. I think there's a lot to be learned from that.
"As much as it's a game and it's a passion of ours and we love it, Mo has life in perspective. I think that is what we all marvel at, that's what we all look up to him about."
Bryan Hoch is a reporter for MLB.com. Follow him on Twitter @bryanhoch and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.