Almunia saved a Chris Brunt penalty but gifted Gonzalo Jara the second of the Baggies' three second-half goals.
Not even Samir Nasri's late double saved the previously-unbeaten Gunners from their first loss of the season, 3-2.
Wenger: We made it more difficult because we were not at our usual level. Not defensively, not offensively. Overall everything was difficult for us today - passing the ball, winning the ball back, winning the one against ones - and we got what we deserved which was zero points. We didn't deserve more. The positive is that we did fight until the last minute but it was just not good enough at that level to get three points. I didn't recognise my team today'
Laurent, Marouane, Alex and Samir look dejected as West Brom scores their first goal.
Great Manuel saves penalty!
Well, life goes on. Get soon well Cesc, Robin, Theo, Nicklas, Thomas, Kieran, Aaron.