Its great that Jenkinson was a youth player and a huge Gooner but he is just isn't good enough for this level. Its not just his skills either but his positioning and football IQ.
The first goal was fucking awful. It was a very nice ball to switch the field but its Fullback 101 that you need to watch the winger and maintain a position that you're close enough to close the man down and keep him from having ages to freely pick a pass into the box if the ball is swung to that side.
The second goal just as bad. Jenks loses the ball trying to do God knows what, leaving his man clearly ahead of the play. If his first reaction had been to sprint back, he would have time to get there because the ball is carried into the center a while before being pulled out to the wing. But, no, his first reaction is to moan a little bit, then stroll pointlessly after the man with the ball, then start jogging toward the middle of the box when he finally realizes there is a legitimate threat (due to his man being all alone on the wing).
Let AMN or Holding play every game at RB until Bellerin returns.