Erisken was largely ineffective during the first half but started having an impact on the game once the Danes began playing more passes.
With an exciting attack consisting of Andre Carrillo, Christian Cueva, Edison Flores and Jefferson Farfan, Peru were a constant danger to the Danish defence, stretching Andreas Christensen and Simon Kjaer.
"Of course it was an emotional game", Poulsen told reporters.
Peru's build up to the tournament was overshadowed by the controversy over Paolo Guerrero's selection.
Despite creating 14 chances and having 17 shots, Peru hit the target just six times, never truly testing Kasper Schmeichel as much as they should have given their overall domination of the match.
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Another chance was squandered soon afterwards when Farfan was teed up on the penalty spot but despite making a clean connection with his shot, Schmeichel managed to stick out a leg to keep the ball out.
The referee initially waved Peru's appeals away after Cueva appeared to be tripped by Poulsen but as play continued, the decision was being reviewed and the official eventually halted the action to point to the spot.
With 11 minutes left, Guerrero almost scored one of the goals of the early stages of this tournament with the Flamengo forward sending a back-heel towards the far bottom corner from 10 yards, only to watch on as the ball went agonisingly wide with Schmeichel beaten. "People make mistakes and we have to try and turn things around".
Cueva had the best chance to open the scoring just before half-time when Peru were awarded a penalty.
And in the second-half, the midfielder could not find his way back into the game, looking void of some confidence following his penalty miss.
Denmark head coach Age Hareide fears he may have lost William Kvist for the rest of the World Cup after battling past Peru in a 1-0 victory. Midfielder Christian Eriksen is expected to lead the Danes after scoring 11 goals in World Cup qualifying match and a hat trick in the decisive playoff that clinched Denmark's place in Russian Federation.
If you weren't a Peru fan before, you probably are now.