Down 2-0, the Spaniard came off the bench to score a stunning solo goal. Troy Deeney eventually took the game to extra-time before Deulofeu bagged his second of the game to seal the club's first FA Cup final appearance since 1984.
"In that moment, I think he was angry when he started to play," Gracia told a post-match news conference.
"But I like to see my player this way, with that attitude. He felt angry in this moment, to show what he is able to do and he helped the team by scoring two important goals.
"The first one is high quality but it is not a surprise for me because I see him in all the training sessions.
"He always accepts the decisions and he knows in other moments there will be other players in the same situation.
"I suppose he will be angry in that moment because he wanted to play the semi-final. He has played almost all the games before and he wanted to help the team. He has done it.
"We knew before the game when we started with other players that Gerard would be important during the game. I knew it, with more spaces. What I didn't know is we would be losing 2-0."