(CNN) Christian Eriksen "was gone" before being resuscitated from cardiac arrest, Denmark's team doctor said at a press conference Sunday.
The Danish soccer player collapsed on the pitch during his team's opening Euro 2020 match against Finland.
"Well, what should I say? He was gone. And we did cardiac resuscitation and it was cardiac arrest. How close were we? I don't know," said Morten Boesen.
"We got him back after one 'de-fib,' so that is quite fast," the team doctor added, referring to the defibrillator used to revive Eriksen. "The details...I am not a cardiologist, so the details about what happened and further I will leave to the experts."
Eriksen sent greetings to his Danish teammates from hospital where he is recovering after falling on the pitch shortly before halftime.
"This morning we have spoken to Christian Eriksen, who has sent his greetings to his teammates. His condition is stable, and he continues to be hospitalized for further examination," the Danish Football Association said on Sunday.
The match was suspended following prolonged efforts from the medical staff to resuscitate Eriksen with CPR and the defibrillator.
UEFA later announced that the match would resume. When the match restarted, Finland won 1-0 thanks to a 59th minute goal from Joel Pohjanpalo.
"We would like to thank everyone for the heartfelt greetings to Christian Eriksen from fans, players, the Royal Families from both Denmark and England, international associations, clubs, etc.," the Danish FA also said in Sunday's statement.
Denmark coach Kasper Hjulmand said that Eriksen wanted his teammates to play and that he was more concerned with his teammates and his family.
The 29-year-old midfielder currently plays club football for Inter Milan, moving to the Serie A side in 2020 after seven years with Tottenham Hotspur in the English Premier League.
"The important thing is that he is well, but there had never been any episode that, even remotely, had hinted at a problem, neither when he was at Tottenham, nor at Inter. In Italy, controls are very rigorous," Inter Milan team doctor Piero Volpi told Gazzetta dello Sport Sunday.
Inter Milan chief executive Giuseppe Marotta said Eriksen has never had Covid-19 and was never vaccinated.
"We don't want to be intrusive because it's right for the player to be calm. He is a champion," he told Italian television channel Rai Sport, according to Reuters.
The Danish talisman, who has more than 100 caps for his country, came through the youth ranks at Ajax and started his professional career with the Dutch club.
Denmark next play Thursday against Belgium. Hjulmand added that he will try to get the team back to a normal routine on Monday.
After he collapsed, Eriksen's Danish teammates formed a wall around him to protect the Inter Milan star from view as he was receiving treatment. Players from both teams, as well as fans in the stadium, were visibly distressed as Eriksen was being attended to by medics.
In Group B's other match, Romelu Lukaku opened the scoring for Belgium over Russia and ran over to the camera to send a message of support to his Inter teammate. "Chris, Chris, sterkte jongen (Dutch for 'wish you strength/all the best'). I love you!" he said.
Lukaku, who scored a second goal late in the game, told journalists in his post-match interview that he "cried a lot" and "was scared" when he first heard news of Eriksen's collapse.
"I spend more time with him than with my family, so my thoughts are with him, his girlfriend, his two kids and his family," he added.
In Goyang, South Korea, Eriksen's former teammate Son Heung-Min scored a goal in his team's 2-1 victory over Lebanon in a World Cup qualifier, and shouted "Christian Eriksen, I love you", according to a tweet from his club Tottenham.
Other goodwill messages from around the world flooded social media. Harry Kane, the England captain and former teammate of Eriksen, sent his love to the Danish talisman and his family in a tweet Saturday.
"Stay strong mate," said Kane, who will be playing in his first game of Euro 2020 Sunday afternoon.
Saturday's incident was reminiscent of Fabrice Muamba's collapse in 2012, after the footballer suffered a cardiac arrest during Bolton's FA Cup match against Tottenham. Muamba eventually recovered but had to cut his playing career short.
"Please God," Muamba tweeted following Eriksen's collapse.
"All of our thoughts are with Christian Eriksen and his family," Eriksen's former club Tottenham tweeted, while his Inter Milan teammate Ashley Young wrote: "PLEASE BRO PLEASE."
The Duke and Duchess of Cambridge paid tribute to the medics who ran onto the pitch to help Eriksen, and to referee Anthony Taylor, who stopped the game immediately.
"Encouraging news about Christian Eriksen, we are all thinking about him and his family. Well done to the medical team and Anthony Taylor for their calm and swift action," said a tweet from the royals' official Twitter account, signed off "W."