Plymouth Albion head coach James Shanahan has apologised to the club's supporters for the first-half display in the 22-20 defeat by London Scottish.
Albion trailed 10-7 at the break and a red card for Brett Beukeboon did not help as Scottish snatched a late win.
"The first 40 minutes were embarrassing - it wasn't good enough.
"There was no energy, intensity or anything we'd worked on and talked about during the week," Shanahan told BBC Radio Devon.
"I'm hugely disappointed. I apologise to the supporters and the sponsors for our first-half performance because it wasn't good enough.
"We applied ourselves on the pitch for one minute and we scored a try, and played with some pace and tempo but that was it."
Winger Tom Bowen was also sin-binned during the game and indiscipline has been an issue for Albion so far this season, with six yellow cards and a red in their first four matches.
"Red cards and yellow cards don't help anyone - you're not going to win a game playing with 14 men.
"Beuks and Tom have apologised to the squad, but that really hurt us," Shanahan added.
"The sending off was the turning point of the game. We'd just got back in to the game and scored a good try and there was a bit of a buzz. The red card put us under the cosh and it was only a matter of time before they made use of it.
"We nearly came back to win it and probably should have had the composure to win it in the last few minutes."
Beukeboom has been suspended for four weeks by the club, but could still face disciplinary action from the Rugby Football Union.