A magnificent 87th minute strike from Saddlers winger Jamie Paterson settled the contest and left Boro five points shy of the play-offs in 12th position.
Smith said: "I thought the match had 0-0 written all over it. It was a really difficult surface, but playable.
"Other than the strike (Walsall's winner) I thought the game was instantly forgettable. We had the two best chances in the first half, and in the second Greg Tansey had a terrific strike which was deflected wide.
"We have lost three on the spin and I think its the first time that has happened with the group I have.
"Now its not really about looking at the top six or 70 points, it's a matter of getting back on track, but too many guys have had a dip in form.
"We will come again. The first half of the season has been really good, it's just the last month that has seen a dip in our form. We would like to think we can still challenge for the top six."