Gary Bowyer rued his side’s first-half showing, as they fell to a 2-1 defeat at in-form Plymouth Argyle.
The Bantams conceded two goals in the opening 25 minutes at Home Park, and proved unable to reverse the deficit, following the interval.
The City manager believed the standards - prior to the break - were not as high as he has come to expect, and put the defeat down to this.
"Ultimately, we were second best, in the first half," said Bowyer.
"For the first time this season, the standards we delivered were nowhere near the standards we set.
"You cannot come here - to play against a good team with good players - and give them a two-goal headstart, like we did.
"It does not really matter who we are or where we are in the league, the game will always be difficult if we let our opponents get the better of us.
"It was definitely a learning curve, for us."
Despite an improved performance in the second-half, Bowyer was adamant plenty of work is still to be done.
City pulled a goal back, shortly after the interval and pushed - late on - for and equaliser, though the Bantams boss expected better.
He added: "The manner of the two goals we conceded were soft but we got into half-time, made the changes, got the early goal - which we needed - and kept going.
"That is the minimum of what is required, though. We had a lot of opportunities where we should have scored, with a big one falling to Zeli Ismail.
"The endeavour was there in the second half, but not in the first half. It was not to the standard we set.
"We go again, now. I would just like to say a massive thank you to the supporters who travelled down. In the second half, we gave them something to cheer about, but it was not enough."
Bowyer’s men are back in action at Macclesfield Town next Saturday. CLICK HERE to purchase tickets.