Inter midfielder Eriksen was given CPR on the pitch during the first half of Saturday's game in Copenhagen after collapsing with no other players around him.
Denmark team-mate Kasper Schmeichel reported on Monday that Eriksen was "smiling and laughing" in hospital, while team doctor Morten Boesen confirmed the 29-year-old suffered a cardiac arrest.
Boesen said Eriksen "was gone" before being resuscitated on the field.
Now Eriksen has revealed the first picture of him in hospital, giving a thumbs-up gesture.
He wrote in a message posted to the Danish Football Union (DBU) Twitter page: "Hello everyone. Big thanks for your sweet and amazing greetings and messages from all around the world. It means a lot to me and my family.
"I'm fine – under the circumstances. I still have to go through some examinations at the hospital, but I feel okay. Now, I will cheer on the boys on the Denmark team in the next matches.
"Play for all of Denmark. Best, Christian."
The DBU on Monday described Eriksen as being in a "stable and good" condition.
In a statement issued by his agent, also on Monday, former Ajax and Tottenham midfielder Eriksen thanked those who assisted him and vowed to get to the bottom of what caused the cardiac arrest.
Denmark skipper Simon Kjaer has been widely praised for stopping Eriksen from swallowing his tongue and placing his stricken team-mate in the recovery position.
UEFA originally suspended the fixture, but it was agreed the match would resume from where it left off less than two hours later, with Finland winning 1-0.