The Baggies were hit by four goals at Carrow Road, resulting in the side's biggest home loss of the season.
"We're not disappointed, more like a little embarrassed," Brunt told the club's official website. "We didn't create much and every time Norwich went forward they looked like scoring. We simply weren't good enough. It's not like us at all. We haven't been like it all season.
"Norwich played like a team who needed to win and they got what they deserved. They were miles better than us. Four goals didn't really flatter them. We had a lot of fans who made a lot of effort to go all the way over there. We let the fans down and we let ourselves down."
The Baggies are currently eighth in the table with one game left to play.