Promising young striker Johnny Russell was the Terrors' hero as he produced what proved to be the winner after just 17 minutes, and McNamara felt his side were worthy of the three points.
"It's a massive three points especially after Saturday," he said. "Motherwell have some good players who can hurt you.
"However, our keeper didn't have many saves to make while theirs was man of the match.
"I thought it was a great team performance, we passed up a few good chances before James McFadden came on and I must admit I feared the worst.
"I said to the lads before the game that clean-sheets will win you games, we have to make sure we defend well as a team.
"Some of the players we have at our disposal are fantastic talents, guys like Johnny Russell and Gary MacKay-Steven were excellent."