The former England international teed up both goals in the stunning 2-0 win at Arsenal in the last eight.
Head coach Dario Vidosic has challenged his side to win a first ever major trophy for the club.
Kirby said: “It’s something we talk about. We know the people we have in our changing room.
“We know they are getting more hungry.
“We know there is a real belief in the changing room and this is going to be massive for us.
“Winning against a team like Arsenal and knowing we can go into the semi-final with the confidence, it was really important.
“I am just really happy we are able to go into that semi-final.”
Vidosic returned home to Australia for a period recently around the death of his father Rado, who was on the Albion staff last season.
Kirby said: “It was a really tough time when Dario lost his dad Rado for everyone at the club.
“It was his (Rado’s) birthday yesterday so happy birthday Rado and I really hope you are proud of us and everything we were able to achieve.
“To get to a semi-final for your son, for everybody and for your family.”