Denmark scored the second-fastest goal in European Championship history but Belgium advanced to the knockout stages after Kevin de Bruyne orchestrated a 2-1 comeback victory in their Group B match on Thursday.
Denmark had the perfect start when midfielder Pierre-Emile Hojbjerg intercepted the ball to feed an unmarked Yussuf Poulsen, who arrowed a right-footed shot into the bottom corner with 99 seconds on the clock.
Belgium were poor in the first half but equalised nine minutes into the second from a counter-attack when Romelu Lukaku used his power to drive the ball forward and found De Bruyne, who squared the ball for Thorgan Hazard to score with a tap-in.
De Bruyne then broke Danish hearts when he gave Belgium the lead in the 70th minute, receiving the ball at the edge of the box from a slick passing move and firing a left-footed shot that beat goalkeeper Kasper Schmeichel.
Belgium have a maximum six points from two games, while Denmark are bottom of the group after two losses. Russia and Finland have three points each after two games.