Lamine Yamal, Nico Williams, and Victor Munoz missed the game because of injuries and remained at the team's training base in Tennessee.
Oyarzabal opened the scoring after just two minutes, Pedri doubled the lead in the 32nd and goalkeeper Pedro Gallese scored an own goal in the 53rd to give Spain a 3-0 lead.
Jairo Velez netted in the 66th for Peru, who missed out on qualifying for the World Cup.
After Cape Verde on June 16 in Atlanta, La Roja face Saudi Arabia on June 21 at the same venue and Uruguay on June 26 in Guadalajara, Mexico.
Earlier on Monday (Tuesday AEST), Michael Olise completed his hat-trick with a brilliant curler as France beat Northern Ireland 3-1 in Lille.
It was also the last game on French soil for coach Didier Deschamps, who steps down following the World Cup after 14 years in charge of Les Bleus.
Olise netted from close range in the 43rd minute after Dembele's shot was blocked, then grabbed his second in the 49th, blasting in from near the penalty spot after the visitors failed to clear a cross from the right.
Saving the best for last, the fleet-footed winger broke off the right wing and bent an unstoppable shot into the top left corner from 20 meters in the 75th.
After Olise's second goal, France's defence went napping and Patrick Kelly tapped in a cross midway through the second half for Northern Ireland.
Two-time champions France — runners-up to Argentina four years ago — open against Senegal on June 16 in New Jersey.
And in New York, Liverpool forward Cody Gakpo's second penalty gave the Netherlands a scrappy 2-1 win against Uzbekistan.
His first came in the 32nd minute, but poor defending allowed Fabio Cannavaro's side to level in the second minute of first-half added time. When the Netherlands were awarded another penalty, Gakpo slotted in his 21st international goal.
Ronald Koeman's men open their campaign against Japan in Dallas on June 14.
The Dutch lost the 2010 World Cup final to Spain in Johannesburg.
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