While it was Howard that made the blunder that led to what proved to be the winning goal by Nikola Kalinic, Moyes criticised his side's poor attacking play in the 1-0 defeat.
He told Sky Sports: "The goal changed things. It happens. It was costly, though, a deciding moment in the game. But Tim has been really good for us.
"But that's what happens in the Premier League the players are very good and if you make a mistake you are punished for it."
He continued: "Blackburn did a job on us and we were unlucky, but we certainly didn't deserve anything because of our attacking play.
"We didn't attack well enough, but we defended well I thought. They kept the lead they had and defended it well.
"The big disappointment is that we didn't get enough opportunities at goal, but you have to give credit to Blackburn as they made it hard to get through.