Interim Saints coach Alan Dickens admitted that Teimana Harrison was 'living dangerously' when he thrust his head towards Bath's Nathan Catt in the closing stages of Friday night's Anglo Welsh Cup semi-final.
Despite there being very little contact, the Saints man was sent-off for his headbutt on the Bath forward 13 minutes from time, and it proved to be costly for the visitors as they were beaten 13-12.
Harrison's indiscretion happened with Saints leading 12-10, but with Josh Lewis landing the resultant penalty to put Bath 13-12 ahead, there was no way back for the 14-men of Northampton.
Asked for his thoughts on the sending off afterwards, Dickens said: "Look, there is contact there and they have come to the decision that it is a red card, so we will have to wait and see what happens.
"There is minimal contact, but if you do that then you are living dangerously."
Saints looked to be heading into next Sunday's final as they fought back from 10-0 down in the first half, with Bath scoring the only try of the game through Levi Douglas, to lead 12-10 going into the final stages thanks to four penalties from the reliable boot of Stephen Myler.
But it wasn't to be, and Dickens was left to rue an opportunity missed.
"We spoke this week that we would have to do it the hard way, and we certainly made it difficult for ourselves with playing the closing 15 minutes with the red card," he said.
"In terms of how the players played today and their attitude and commitment, it was there for everybody to see.
"I have just looked at the stats, and it was a very, very even game."
The game was played in appalling conditions, with heavy rain falling throughout, and large puddles forming across the playing surface.
"It was one of those games where it is probably better not to have the ball," admitted Dickens.
"I felt that at times, especially in the first half and in the first 10 minutes, we went through too many phases with the ball instead of just sticking it long.
"We spoke at half-time about kicking long and putting them under pressure, and the other thing that was a struggle was that our lineout didn't function in the second half.
"We got into good positions and we then coughed the ball up at important times."