Truro City boss Lee Hodges was left disappointed after two late goals saw them go down 2-0 at high-flying Chelmsford in Blue Square Bet South.
Max Cornhill's free header from a corner gave the visitors a 78th minute lead before Kezie Ibe got a second two minutes before full-time.
"You can't afford to give someone time just to head the ball into the back of the net," Hodges told BBC Cornwall.
"At this level we'll get punished every time for that."
Hodges had felt that his side had done well against a Chelmsford outfit that is now second in the table after the win at Treyew Road.
"They weren't really creating any clear cut chances and the way we were playing we were holding a good line, I felt we were solid and it could have petered out to a 0-0.
"But one silly moment where a corner's come in and it's a free header and it's cost us the game.
"I had a few choice words to say after the game because the effort they gave out there I can't ask any more," he added.