Newcastle United boss Steve Bruce admits Jetro Willems' debut was marred by a tactical mix-up.
Defeat to Arsenal was decided during a period of uncertainty which eventually led to Arsenal grabbing the winner.
Willems came on as sub on 53 minutes but moved into the wrong position before Arsenal scored as he was finding his feet in the game.
After the match Bruce explained: "It was just a lack of communication with him.
"I wanted to put Matt Ritchie inside and play him (Willems) in his position.
"He only played there (in midfield) for two minutes really until we got the information down about where we wanted him to play.
"That was quickly sorted out, not a problem."