While he admits his frustration at not winning the match, Smith acknowledges that his side showed their quality through much of the game.
"We are disappointed. We got such a handy lead to begin with and then we sat back and admired our good work," Smith told BBC Sport.
"We showed good fighting qualities to come back from that but it is embarrassing to score two tries and go to sleep.
"We did some good things, but defensively we were a shambles and that's very disappointing as last week against Worcester we could have played for three hours and not conceded."
Irish remain four points ahead of Sale in the table in 10th place, while the latter move eight points clear of basement club London Welsh with 18 points.