Ferguson had a pop at Carlos Tevez's recall and whether Mancini actually had the decision taken away from him.
Platt said: "It seems it [Ferguson's comments] was a bit tongue in cheek and there was a bit of fun there - I don't know.
"But he just laughed, Robbie just laughed. It's not a problem to him. It's not about him and it's not about Sir Alex. It's about the two teams alone and apart.
"Robbie wants to win. He's done it before. As regards the pressure on him, it's not about whether he handles the pressure so much as it's about whether the players go out and get the results.
"He's fine. He's beyond fine, seriously."