Quarterback Matt Ryan was sacked three times by the Saints defense and threw a late interception to cost his side the game due to pressure from the home side's pass rush.
Smith told reporters: "We have to protect the quarterback a lot better than we did today, but there's a lot of things we have to do better. He (Matt Ryan) was hit entirely too many times today and that's one of the things we have to correct.
"From the very beginning for any position group they are a unit and not one specific person. It's a unit and they have to grow together as a unit to protect the quarterback better than they did today."
Atlanta face the St Louis Rams next week.