Despite leading 2-1 having fallen behind, a concession of two goals in three minutes allowed the Steelmen to walk away with the three points.
“I just think we were really poor on the day and when you have performances like that you have to hold your hands up and say the best team won.
“We started extremely sloppily in terms of our possession, cheap turnovers, passing the ball out of the pitch. I think Motherwell fed off of it and it gave them a lift. We deserved to go behind because they were the better team, although I think the goal is avoidable.
"We didn’t move the ball quickly enough today and we played into Motherwell’s hands a lot.”
Goodwin was reticent to play too much on his Aberdeen side still gelling with nine summer signings involved.
“We’ll take the criticism,” he said. “There’s been a lot of plaudits recently. We had a great League Cup group stage, if you want, and had a good performance last weekend against St Mirren and got plenty of pats on the back.
“Today we weren’t at it and too many had below par performances. It was as simple as that. You can afford to carry one or two and still get a result, but I just felt there were too many who weren’t at it, myself included.
“We just need to make sure we don’t have too many days like this. It’s not time for pushing the panic button or anything like that."
It is now six points out of a possible nine for Motherwell and their new boss Steven Hammell.
"The performance was good, seeing the fans at the end was good and seeing the players in the dressing room afterwards was the best,” he said.
"The way they bought into what we asked of them in such a short space of time and the work they've done. That along with the quality and the character they showed was all pleasing to see and the reaction to going behind.
"I thought we could have been a bit more clinical in front of goal with our chances but a win up here is a magnificent result."