Uwe Rosler believes Brentford could have wrapped up their Carling Cup first-round tie long before Hereford scored to win.
New Bees boss Rosler began life at Griffin Park with a 2-0 victory over Yeovil on Saturday but could not maintain his winning start in the cup after Yoann Arquin's 92nd-minute winner gave the Bulls a 1-0 victory.
He told the club's official website: "We were very happy with the way we started the game, after 20 minutes the game should have been over.
"We controlled the game for 75 minutes, the last 15 minutes they came on.
"You have days like that but when you do you have to keep a clean sheet.
"We had enough chances to have won the game, in your good periods you have to score goals and that is what cost us."