The Baggies lost 3-1 and after the game Northern Ireland star Brunt believed a coin had been thrown at him by the fans and struck him in the face.
He said: “I was walking towards our supporters at the end, and they thought it was okay to throw a coin at their own players. I’m disgusted.
“If they want to come forward and say they don’t like what they’ve seen then that’s fine. Fans are frustrated we were 1-0 up and lost.
“They paid a lot of money to come, but a small minority spoilt it. There were young kids there. I was absolutely disgusted and ashamed.”