Jack Ross felt Oxford United's late equaliser against Sunderland should not have stood.
The Black Cats were set to take all three points from the Kassam Stadium before substitute Marcus Browne scored with just minutes on the clock.
The goal was assisted by former Sunderland loanee Jerome Sinclair, but Ross felt he should have been penalised for a foul on Jimmy Dunne in the build-up.
"I think it’s a free-kick," he said.
"As I always say, I’ve got the benefit of watching it again.
"It’s not a ridiculously bad decision, it’s not like Jerome [Sinclair] has cleaned him out.
"It’s probably one of the easier free kicks to give throughout a game, so not to get it is highly unusual.
"It does affect the game, I’m always loathed to use refereeing decisions as an excuse but at that time in the match, how the match was poised, it obviously has an impact on the result which is frustrating and disappointing.
"It’s a free-kick.
"I still think we could defend it better from then, I think Jack should stay on his feet rather than committing to Jerome in the box.
"It’s very frustrating for us."
The draw leaves Sunderland fourth in the League One table.
They are behind Portsmouth, Barnsley and Luton Town, but have at least two games in hand on all three of those teams.