Arsenal's downfall once again was its porous defense with Craig Dawson heading in twice from corners on another day of protests against Wenger.

In the skies above the Hawthorns, a plane trailing a banner reading "No contract Wenger out" appeared during the game. Inside the stadium, "Enough is enough time to go" posters were also held aloft by fans who want the Frenchman to leave at the end of the season after 21 years in charge.

In the last month, Arsenal has been eliminated from the Champions League by Bayern Munich and only won two games — both against fifth-tier teams in the FA Cup. Arsenal is further than ever from winning the Premier League title for the first time since 2004 and is five points adrift from the fourth Champions League place.

Arsenal fell behind in the 12th minute in central England when Dawson glanced in his first header from Nacer Chadli's corner.

Although Alexis Sanchez equalized inside three minutes, West Brom regained the lead in the 55th when substitute Hal Robson-Kanu scored with only his second touch of the game by putting the ball under substitute goalkeeper David Ospina.

The crossbar prevented Arsenal leveling again through Danny Welbeck's header before Dawson sealed the win from a set piece in the 75th minute.