Herrera: Improvement in finishing essential
Herrera was encouraged by his side's performance in Massachusetts on Friday, despite their loss, which came after Bruno Alves netted in the 93rd minute.
Mexico enjoyed several good spells during the match but failed to finish off their chances - something Herrera knows must be improved on.
"It was an extraordinary match. The team showed it is made to achieve important goals," Herrera said.
"As I said in the (last) match, we haven't been that convincing when facing goal, so we have to work on it.
"We have to work as well in paying attention at the end. We mustn't lose a game in the last 30 seconds when we had dominated it."
Midfielder Hector Herrera was also upbeat after the loss and echoed his coach's view on their play in the final third.
Javier Hernandez was guilty of missing a host of chances in a 1-0 friendly loss to Bosnia-Herzegovina on Tuesday and was dropped to the bench as a result.
But Oribe Peralta and Giovani dos Santos failed to take advantage of the chance to shine, leaving the coach in the dark as to his best forward pair.
"It was rather positive," Hector Herrera said.
"Overall I think we have had good games and today it was one of them when we played great football. I think we had clearer chances than they had.
"We missed forcefulness. I know we have to improve this because in the World Cup's games there are just three games and we won't have error margin.
"I am happy because things are running well and the group is very solid."
Mexico open their World Cup campaign against Cameroon on June 13.