Eriksen, 29, suffered a cardiac arrest in the 42nd minute of Denmark's opening game against Finland last Saturday and remains in hospital. Denmark manager Kasper Hjulmand said Eriksen watched the match from a hospital located just 500 metres from the Parken Stadium in Copenhagen.
Denmark, who lost the match 2-1, took the lead after two minutes when Yussuf Poulsen slotted home a clinical finish, sparking emotional celebrations inside the stadium, and eight minutes later the match was paused. Both sets of players, coaching staff and supporters gave a minute's applause for the midfielder at the stadium.
A banner was also displayed among fans in one of the stands, which read: "All of Denmark is with you, Christian."
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Before kickoff, a large flag in the shape of a Denmark shirt with Eriksen's name on the back was unfurled on the pitch. Eriksen wears the No. 10 shirt for his country.
Lukaku sent his best wishes to Eriksen in Belgium's 3-0 win over Russia after he scored the opening goal and ran to the pitchside camera and said: "Chris, Chris, I love you."
And after Thursday's match, Lukaku praised the Danish team, saying they "saved my friend's life."
"I respect them as men. They saved my friend's life and I appreciate that. Their character today was incredible. I had to put my feelings to one side in the first half, because I was thinking of Christian. Denmark must continue to believe in it and complete the job against Russia," he said.
Denmark have zero points from their first two matches, but still have a chance to reach the knockout stage. They will need a win in their final group game against Russia and a favorable result in the group's other match between Belgium and Finland. Hjulmand said on Thursday that his side are eager to ensure they can prolong their stay in the tournament.
"With Christian in our minds and our hearts, we know that he's still here, we know it's going to be a tough few weeks for you Christian, we're here for you," Hjulmand told a media conference.
"We're going to stick together and we're gonna beat the Russians, we're not done in this competition."
Despite the loss to Belgium, Eriksen passed on his congratulations to the team when they returned to the dressing room, striker Martin Braithwaite said.
"He sent us a message in the WhatsApp group. I think he said that we were really awesome, I haven't had time to look, but there was a message when we entered the dressing room," Braithwaite said.
A number of teams have paid tribute to Eriksen during the tournament. Before their 1-0 defeat to Russia on Wednesday, Finland players wore T-shirts during the warm-up with words "Get well Christian!'' on the front, while Austria's Michael Gregoritsch and Stefan Lainer held up a T-shirt which read: "Eriksen stay strong" after scoring goals in their opener against North Macedonia.
Eriksen gave an update on his condition on Monday in his first official communication since collapsing and said: "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 OK. Now, I will cheer on the boys on the Denmark team in the next matches. Play for all of Denmark. Best, Christian."
Meanwhile, the Danish Football Association has called on UEFA to change its procedures following Eriksen's collapse and the subsequent decision to resume the game.
The players were offered the chance to restart the match the same evening or at 12 p.m. CEST (6 a.m. ET) midday on the following day.
UEFA has come in for sharp criticism from Denmark legends Peter Schmeichel and Michael Laudrup, with the latter saying the choice of resuming on either Saturday or Sunday was not a choice at all.