Smith refused to put all the blame on the Ibrox club's exit from the Champions League on Jean-Claude Darcheville's incredible miss during the 3-0 defeat by Lyon. Darcheville came on as a second-half substitute for Sasa Papac as the Light Blues trailed to Sidney Govou's first-half goal.
After seeing Steven Whittaker clear a Karim Benzema shot off the line, Darcheville found himself only six yards from goal when skipper Barry Ferguson's cross from the right sped across the Lyon goal. With the Rangers fans ready to acclaim the equaliser that would have sent them into the last 16, Darcheville somehow blasted his effort over the bar.
Benzema's late double compounded a miserable night for the home side as did a last-minute red card for Darcheville following a reckless challenge on Kim Kallstrom.
Smith said: "It was obviously a factor in the match but the game in itself was similar to the game in Lyon. We got the first goal there which forced the opposition to come forward. Lyon left themselves open to the break as we did tonight.
"The miss at that time was obviously an important factor so to be fair, maybe one balances the other. Never mind Darcheville's attempt, one of the most disappointing aspects was the way we lost the second goal.
"We were reaching the stage of the game where nerves were coming to the fore, we were getting the ball in to the box more than we did at any other stage of the game and to lose a simple goal in the manner that we did, which effectively killed the game, was disappointing."
Smith added: "The margin of error is the Champions League is very tight. "I couldn't have complained about my team's second-half performance up until we lost the second goal.
"We didn't play that badly overall, we just lacked a cutting edge when we went into the last third of the pitch."