Swansea City manager Steve Cooper accused referee Tony Harrington of being influenced by the Bristol City bench in his decision to send off Jake Bidwell.
The Swans boss was angered by the decision to dismiss Bidwell who was given a straight red card during the late stages of Saturday’s 0-0 draw at Ashton Gate.
Harrington consulted an assistant before showing a red card to the full-back for a late challenge that prevented Robins substitute Niclas Eliasson from breaking away on the right.
Only stoppage time remained and the Swans held out comfortably for a point from a game they dominated for periods, particularly in the second half.
Cooper said: “It was a foul and an obvious yellow card, but to send Jake off was a poor decision.
“Their bench reacted, which may have influenced the ref, but he should have been stronger. I have spoken to him and he told me his assistant felt it was a red card.
“Whatever the case, most people who saw the incident would have thought a caution sufficient.
“I don’t like to see players sent off. Bristol had a defender booked early and he committed a couple more fouls after that, but not enough to justify a sending-off. He stayed on the pitch quite rightly. But both teams should have finished with 11 men. I will look at the process and the history of appeals before deciding whether to make one.”
Unsurprisingly, Robins manager Lee Johnson saw the incident rather differently.
He said: “From where I was standing it looked as though there was an intention to hurt Niclas, rather than just impede him.
“It could have been a yellow card, but if it had been, they would probably have got away with one. I don’t think an appeal would be successful.
“It was a day when two workmanlike sides went toe-to-toe. I would have been disappointed with a draw before the start, but the way the game went a point each was probably about right.”
The first half was slow to ignite, Swansea having plenty of the ball and looking a threat without managing a serious goal attempt in the opening half hour.
Bristol City were just as ineffective going forward and after 29 minutes their head coach Lee Johnson made a change, sending on striker Famara Diedhiou for centre-back Nathan Baker. Tommy Rowe dropped from left wing-back into the back three.
Immediately, the home side looked more dangerous, as Diedhiou got himself involved, and a Josh Brownhill free kick from 25 yards brought the first save from Freddie Woodman.
Moments later Andreas Weimann fired over from distance and Diedhiou went close to breaking the deadlock in the 39th minute, sliding in to connect with a Callum O’Dowda cross and seeing his effort graze the far post.
It had been a quiet half for home goalkeeper Dan Bentley until injury time, when he had to dive to his left to parry a 30-yard free kick from Swans skipper Matt Grimes.
Swansea began the second half on the front foot, Bersant Celina forcing a save from Bentley with a well-struck free kick from the left.
Johnson responded with a second substitution on 51 minutes, sending on Kasey Palmer for Sammie Szmodics, who had not looked comfortable in an advanced role.
Still the visitors looked to be positive and Celina and Jay Fulton went close before Bentley saved from Andre Ayew and Mike van der Hoorn headed over from a corner.
At the other end Diedhiou headed straight at goalkeeper Woodman, but honours finished even.