Moses, a £10million summer recruit from Wigan, has enjoyed considerable game time under the Spanish coach after not featuring too often under former boss Roberto Di Matteo.
He said: "The FA Cup is a massive competition and it would be a big achievement to win it.
"We want to go out there and perform for the manager. He has great experience and we just go out there and try to enjoy ourselves and win games.
"Any player would like to play under Benitez as he is a great manager.
"He has come in and perhaps seen something different in me, has played me and I appreciate it. At such a big club you are going to have squad rotation and that is sensible so you can be ready for every game.
My aim is to work hard every day and do my best for the manager every time I play."