Second from bottom in Group H with one point from two matches having lost 1-0 in Norway and drawn 4-4 at home to Cyprus, Portugal need a win to keep their hopes alive.
Bento could hardly be under more pressure for his first game after replacing Carlos Queiroz, who was sacked last month for insulting anti-doping agents.
The 41 year-old said Portugal needed to take the initiative and could not afford more defensive mistakes.
"We have to play with hot hearts and cool heads. There is no margin for error. We need to play with ambition, with some risk, but without losing balance," Bento said.
Cristiano Ronaldo missed the first two qualifiers through injury, but will be back for Bento's debut. The forward disappointed under Queiroz but improving form at Real Madrid provides cause for optimism.
The coach has kept Ronaldo as captain but took some pressure off the world's most expensive player.
"We cannot think that because he is one of the world's top players, he can solve all the problems. We count on his talent... but we cannot burden him with the full responsibility, for that lies with me," Bento said.
MIDFIELD ROLE
Ronaldo's club team-mate Pepe is also back from injury. He was used in a defensive midfield role by Queiroz but Bento hinted that he could return to central defence.
"I think he is more comfortable and prefers playing in defence," the coach said.
Bento's main problem in choosing the starting lineup is in midfield, where he has recalled Joao Moutinho and Carlos Martins after long absences and called up Ruben Micael and Paulo Machado.
With Ronaldo back, Nani is likely to start on the opposite wing and powerful striker Hugo Almeida will lead the attack against the Danes.
Denmark beat Iceland 1-0 away in their first game and will be keen to damage the group favourite's chances.
The two sides also met in the 2010 World Cup qualification, with the Danes winning 3-2 away and drawing 1-1 at home.
"They are an extremely difficult opponent, with players who have good ability and play in the top leagues," Bento said.
He will be relieved that Arsenal striker Nicklas Bendtner is sidelined with a groin injury but goalkeeper Thomas Sorensen has recovered from an elbow problem.
