Denmark midfielder Christian Eriksen is "awake" in hospital after collapsing in the Euro 2020 match against Finland, said the Danish Football Association.
The Group B game was suspended before half-time after the Inter Milan player fell to the ground.
Referee Anthony Taylor immediately called for medical support and Eriksen received treatment on the field.
Eriksen received CPR before the players were taken off the pitch and the match was postponed.
Uefa confirmed the match had been suspended because of a medical emergency.
The UEFA EURO 2020 match in Copenhagen has been suspended due to a medical emergency.— UEFA EURO 2020 (@EURO2020) June 12, 2021
"Following the medical emergency involving Denmark's player Christian Eriksen, a crisis meeting has taken place with both teams and match officials and further information will be communicated," it said.
"The player has been transferred to the hospital and has been stabilised."
The incident happened as a throw-in was played towards him near the end of the first half.
His distressed team-mates surrounded him and the shocked supporters in Copenhagen were visibly upset as the player was treated.
Uefa president Aleksander Ceferin said: "Moments like this put everything in life into perspective. I wish Christian a full and speedy recovery and pray his family has strength and faith.
"At these times, the unity of the football family is so strong and he and his family carry with them the good wishes and prayers of everyone. I heard of fans of both teams chanting his name. Football is beautiful and Christian plays it beautifully."
Saturday's other Group B match between Belgium and Russia, scheduled for 20:00 BST, took place as scheduled.
Belgium striker Romelu Lukaku paid tribute to his Inter team-mate, telling the camera "Chris, I love you" after scoring the opening goal.
Referee Anthony Taylor had immediately called for medical support and Eriksen received CPR before the players were taken off the pitch and the match was initially postponed.
Uefa confirmed that his condition had "stabilised" after being taken to hospital.
"The match has been suspended due to a medical emergency which involved Denmark's Christian Eriksen. The player is now in hospital and in a stable condition," it said.
"Uefa wishes Christian Eriksen a full and speedy recovery and wishes to thank both teams for their exemplary attitude."
The incident happened as a throw-in was played towards Eriksen near the end of the first half.