He was hardly "pressed". The interviewers (perhaps from TC) asked him what it meant, and he gave them a brief, simple explanation. Forget that it matched his gesture. Why would I assume that the guy who once publicly dismissed Djokovic as a joke and classified Nadal as one-dimensional suddenly felt inclined to lie about a winning gesture?
he may have matured, realized he needed to contain his enormous ego and figured out he shouldn't be so blunt like he used to be?