Manager Lee Johnson bemoaned Barnsley's lack of patience as they were beaten 2-1 at home by Shrewsbury Town.
With the scores locked at 1-1, the hosts dominated the second half, but were dealt a killer blow when former-Red Jordan Clark struck in stoppage time.
"It feels horrible. I didn't think we played that badly; in patches we were good, but we need to develop an identity within our play that people trust and believe," Johnson told reporters.
"The one criticism I've got is that I think we resorted to going a little bit too long in the last 15 to 20 minutes. We lost that patience and started to go forward too early."
The result leaves Barnsley in 14th place in League One, having lost three of their opening six matches.