Spurs crashed out of the FA Cup at home to Crystal Palace on Sunday, ending an eight-match unbeaten run, and their dreams of a Treble.
But Son says they need to turn their anger on Fiorentina for the second leg of their Europa League last 32 clash at White Hart Lane.
He said: “Because we lost we are angry, I am angry. But this is football. We have to understand.
“Could it help us in the other competitions? Yeah I think so because it’s now going to the end of the season.