A 2-1 defeat at home to Barcelona sees Inter dumped to the Europa League.
But De Vrij says: "Surely there is so much disappointment for not qualifying, but no regrets.
"We gave everything and had opportunities, trying everything to win. Unfortunately it was not enough. It is gone now, it is not necessary to look back but only to get up immediately and look forward.
"We must concentrate on the next game. Difficulty should unite us, make us even stronger."