Denmark manager Age Hareide singled out Kasper Schmeichel for praise after a string of saves ensured that their World Cup campaign got off to a winning start.
Hareide's team spent most of Saturday's match in Saransk on the back foot but Yussuf Poulsen scored the only goal after Carlos Cueva had skied his penalty over the crossbar.
Denmark have not conceded a goal since Shane Duffy's strike for the Republic of Ireland in their final qualifying match and Hareide was delighted with his team's defensive solidity.
"They [Peru] did a lot to try and get an equaliser. It is now a fifth game without conceding a goal and it is very tough to play against World Cup opponents and do that," said the 64-year-old, as quoted by BBC Sport.
After Poulsen's goal, Peru pushed hard for an equaliser but Schmeichel - who had already pushed away an Andre Carrillo shot in the first half - was equal to efforts from Jefferson Farfan, Paolo Guerrero and Luis Advincula.
Poulsen was named the official man of the match but most observers agreed that it should have been the Leicester City goalkeeper, including his manager.
"He is acrobatic, a very quick goalkeeper and his goalline play is probably the best in the world when he is on form," said Hareide. "He had a fantastic performance and it was needed. You have to acknowledge the performance of Kasper but also the defence and the whole team."
Denmark will now be big favourites to go through from Group C, particularly as their second game is against underdogs Australia in Samara on Thursday.