Denmark started their World Cup campaign with a 1-0 victory over Peru in Saransk thanks to Yurary Poulsen's second-half strike.
Peru were beaten 1-0 by Denmark in their first World Cup finals match since 1982, with Yussuf Poulsen's strike settling the contest after the South Americans missed a first-half penalty.
Christian Cueva blew the opportunity to give the Peruvians the lead just before the interval as he blazed over a spot-kick awarded via the video assistant referee system.
Poulsen, who had given the penalty away with a foul on Cueva, then broke the deadlock in the 59th minute with a cool finish having been teed up by Christian Eriksen.
Peru's all-time top scorer Paolo Guerrero, cleared to play at the tournament in May when a Swiss court granted a temporary lifting of his 14-month drug ban, went close to equalising after coming off the bench as his backheeled effort went wide, before Jefferson Farfan was denied by the foot of Kasper Schmiechel.
While they ended up defeated, with Denmark joining France on three points in Group C, this was certainly a creditable performance from Peru as they made their long-awaited comeback at this level.