Pardew's men were well beaten by their Spanish counterparts in the Schalke Cup clash at the Veltins Arena, conceding three first-half goals in a disjointed display.
Sergi Darder opened the scoring for Malaga with a long-range effort after 26 minutes, and a double from teenage striker Samu Castillejo effectively ended the game as a contest.
Substitute Gabriel Obertan did pull one back on the hour mark, but a Newcastle comeback never looked likely.
Remy Cabella was handed his Newcastle debut, while midfielder Moussa Sissoko made his return following his World Cup exploits with France.
Youngsters Massadio Haidara, Mehdi Abeid, Adam Armstrong and Ayoze Perez were also included in the starting XI, and Pardew believed his team selection was the primary reason for the result.
"I blame myself for that defeat. I put two young lads [Armstrong and Perez] up the top and maybe it was too much inexperience to cope with a team like Malaga," Pardew said.
"It was Moussa and Cabella's first game so really I'm kicking myself because I should have had a bit more experience on.
"Having said that the second half was much better, our experienced boys came on and we're getting there slowly but surely. It was nice to see our new boys getting a run out.
"It's important that our senior players are ready to go.
"We protected a few because we've got another game tomorrow [on Sunday against Schalke]. We haven't got an abundance of senior players and I wanted to save some for what will be a tough game tomorrow.
"We will have a much more experienced team tomorrow. I take full responsibility for that first half. It was perhaps a bit too young."
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