The manager told BBC Sport: "We didn't show enough quality, conceded a poor goal and they sat deep. We needed to use the ball better and we were too loose with our passing. It was not a lack of desire or endeavour but there was a lack of quality.
"It was a soft goal to concede and it gave them a lift and put a little bit more pressure on us. We didn't have enough good moments and we have not really made Ben Foster work hard enough.
"We have taken a step backwards and we have to turn it around against Fulham next week. Losing today makes it an even bigger game. It was an opportunity to get a gap between us and the bottom three and we are now fighting for our lives. I can understand the fans' anxiety and frustration, they don't want to see their team in this position."
The result leaves Norwich just one place above the Premier League relegation zone, while West Brom jumped to 16th.