Steve Cooper was left fuming by the 83rd-minute penalty that cost his Swansea side two points in the 1-1 draw with Bristol City at Ashton Gate.
The visitors looked to be holding on comfortably to the 51st-minute lead provided by Jamal Lowe's fierce angled drive from inside the box.
But then Connor Roberts appeared to lose his footing when trying to intercept a free-kick from the right. Antoine Semenyo went tumbling over him and referee Oliver Langford pointed to the spot.
Nahki Wells chipped home the penalty and Bristol City narrowly avoided a second home defeat in the space of four days.
Swans boss Cooper said: "The lads are really disappointed with a point because of the nature of the equaliser and the decision on the penalty.
"We got the breakthrough, a great finish from Jamal, and looked really settled in the game.
"If anything, I thought we were going to win by another goal. For a decision to be made like that, it's hard to keep my mouth shut to be honest.
"We had talked about this referee in the pre-match build-up. And it was true to form.
"This league is so hard to get points in and to be on the back end of a decision like that is a difficult one to take.
"They had a good chance from a set-piece early on and a couple of shots from areas where I didn't think they'd damage us. Apart from that, I didn't think they were going to score.
"I thought we looked really comfortable in what was a decent game of football. For the boys to defend that well, and then get done like that is hard.
"But it will make us stronger going forward. We aren't going to dwell on the penalty, but speaking straight after the game, it's hard to look past it."
Bristol City head coach Dean Holden agreed with Cooper.
He admitted: "I saw the incident clearly and would have been disappointed if that penalty had been awarded against my team.
"We had a stonewall spot-kick turned down against Middlesbrough on Tuesday night. I didn't think things would even out that quickly, but they did.
"In the end, I am happy with a point in those circumstances. We didn't want to lose two on the trot as it would have damaged confidence.
"Now we will move on, still looking to improve with every game. Swansea are a good team with Premier League players and there were plenty of positives for us.
"Semenyo was a handful and earned his start by working hard. He did well against Northampton in the Carabao Cup and is learning with every match.
"I made five changes because I felt we needed freshening up. It was also a big game for Taylor Moore after his mistake against Middlesbrough and he showed good temperament to handle it well.
"I only took him off near the end to get an extra attacker on. In the end we had four strikers on the pitch.
"The lads showed good character after falling behind and I got a response to Tuesday night's defeat."