Boss Dean Ryan admitted the early red card had disrupted plans for the derby clash with Cardiff – but praised a second half show that was one kick from victory.
The Men of Gwent had lock Joe Davies dismissed after 16 minutes of the rearranged United Rugby Championship clash before visiting hooker Liam Belcher also saw red before the break.
A second half try from the returning Jack Dixon had threatened to secure a home win before Rhys Priestland kicked Cardiff back ahead.
Late drama saw a penalty from Will Reed slide agonisingly wide and Director of Rugby Ryan to reflect on a narrow loss.
“Whatever plan we had went off the table (with the red card),” he said.
“For us to lose Ben Carter was a blow too, but I thought Huw Taylor and Harrison Keddie really adapted well.
“Credit to the team for keeping it cohesive and still winning lineout ball because we didn’t have many men left by the end.
“We had a chance, we had a shot, but we were still too loose and the number of times we bring them into our half hurts us. Somebody like Rhys (Priestland) will punish you.
“In the second half there were bits that I liked about us, and our attack game was causing all sorts of problems.
“Everyone was on the same page, and everyone threw everything at it.
“We were better, but our discipline keeps undermining some of the good things that we do."
Meanwhile, Ryan said lock Ben Carter would be assessed in the week after being forced off with a shoulder injury early in the second half.
“He was struggling for power in his shoulder. It was apparent after he came out after half-time that it wasn’t there,” said Ryan.
“He got a stinger early on and he did well to keep going. Fingers crossed for him, but he certainly lost some power.
“We have one game left now and we have got to get some bodies back, some energy back and finish the season the same way we went about today.”
In the second half there were bits that I liked about us, and our attack game was causing all sorts of problems...