After taking a 29th minute lead through Gyasi Zardes, the Black and Gold let their guard down after recess as the visitors scored twice to register a 2-1 away win.
Brek Shea levelled the score-line by the 51st minute, before Kei Kamara wrapped up the match with a goal 12 minutes to full-time.
"I mean any time you lose you feel concerned about it," Lalas said, as reported by his club's official website.
"A loss is a loss, so I think everyone is disappointed with the result.
"We were up one to nothing and we had control in the game.
"In the second half, we could have done much better, in terms of moving the ball and having a lot of options going forward, but I thought that we lacked that, we didn't really get that in the second half.
"We need to be better as a team, so we will go back next week and work on something."
Significantly, Saturday's result brought an end to Crew's fourteen-match unbeaten run in MLS.
Lalas, who is one of four Ghanaians in the Black and Gold's first team, was very much in the thick of affairs as he lasted for the entire duration of the game.
Right-back Harrison Afful also played all 90 minutes, while central defensive partner Jonathan Mensah was substituted in the 83rd minute.
Midfielder Mohammed Abu, on the other hand, watched on from the bench.