Mandzukic makes debut as Atletico win
The Croatia striker, who joined Atletico from Bayern Munich on a four-year deal earlier this month, was named in Diego Simeone's starting XI for the clash at the Estadio Municipal in Burgo de Osma.
Defender Diego Godin, forward Raul Garcia and midfield duo Koke and Gabi were also involved from the start as Atletico began preparations for the defence of their Liga crown.
But it was 18-year-old forward Hector Hernandez who stole the show by netting the only goal of the game against the second-tier side.
Hector found the net a minute before half-time to ensure a successful start to pre-season for Atletico.
Simeone's side, beaten UEFA Champions League finalists last season, head to San Francisco to take on MLS outfit San Jose Earthquakes at Candlestick Park on Monday.