Roberto Martinez says he has never seen "carefree" Eden Hazard work so hard and is also hopeful of having Kevin De Bruyne back to fitness for Belgium's clash with Denmark.
Hazard has been blighted by injuries during his two seasons at Real Madrid and was not deemed ready to start Belgium's 3-0 win over Russia in Saturday's Group B opener.
The 30-year-old played the final 18 minutes in Saint Petersburg – only his second international outing in 19 months, six days after coming on as a substitute against Croatia.
He managed only 18 touches of the ball during his time on the field, but Martinez is pleased with the progress being made by the Madrid forward to get back to his best.
"I've never seen him work so hard off the field," Martinez said at a news conference on Sunday. "As a captain, he feels the responsibility. From the first day he was with us, he works hard.
"Against Russia, that's the first time I've seen a carefree Hazard. Before that I always saw him thinking on the pitch.
"Now he is playing more intuitively, making moves and getting away from defenders. The challenge now is to last for 90 minutes.
"He worked individually again today, but he will get more minutes against Denmark and even more against Finland, when he should be able to play the full 90."
De Bruyne played no part in Belgium's comfortable win against Russia, secured thanks to a couple of Romelu Lukaku goals and one for Thomas Meunier.
The Manchester City man is recovering from the fractured nose and left orbital he sustained in his club side's loss to Chelsea in the Champions League final two weeks ago.
However, De Bruyne has a chance of being ready in time to feature against Denmark in Copenhagen on Thursday.
"He will resume training tomorrow," Martinez said. "After that we'll evaluate whether he can come to Copenhagen with us to play against Denmark."
Martinez also revealed that Axel Witsel will make a surprise return to action next week, just five months after tearing his Achilles tendon while playing for Borussia Dortmund.
"My idea was to have him start against Finland for the first time," he said. "That's why I named him in the 26-man group.
"But since he is ahead of schedule, he will be given some minutes against Denmark."
Belgium will be looking to build on a run of just one defeat in their last 24 matches in all competitions when they travel to Denmark.
The Danes lost 1-0 to Finland in their Group B opener, a game that was overshadowed by Christian Eriksen suffering a cardiac arrest during the first half.
Eriksen was given CPR on the pitch by medics and is now "awake" and recovering in hospital.
Denmark's players returned to the field less than two hours later and were beaten by a Joel Pohjanpalo goal, with Pierre-Emile Hojbjerg missing from the penalty spot.
"They were not themselves against Finland," Martinez said. "The circumstances with Eriksen weighed on the group.
"We can expect a different Denmark and a very tough game on Thursday. You cannot compare the circumstances
"That will be a very emotional game, especially before kick-off. They have a very strong team, as we know from the Nations League.
"The Danes will also have the support of the fans. But we need those kinds of matches. The match should be a celebration in honour of Eriksen, as it were."
Denmark and Belgium's only previous meeting at a major tournament was in the group stages of Euro 1984, the Danes winning that one 3-2 after recovering from two goals down.