United midfielder Herrera was dismissed for two bookable offences, the second of which came midway through the second half.
Manchester United assistant manager Rui Faria suggested sarcastically that referee Mark Clattenburg did "fantastic work" by sending off Ander Herrera during their 0-0 draw with Burnley.
United midfielder Herrera was dismissed for two bookable offences, the second of which came midway through the second half for a foul on Dean Marney.
The Spaniard appeared to slip as he made the challenge, but Clattenburg ruled it worthy of a booking and issued a red card.
Herrera wasn't the only one to see red at Old Trafford as Faria conducted post-match media duties, with manager Jose Mourinho absent after being sent to the stand for reportedly protesting too strongly at half-time following a rejected penalty appeal.
Mourinho was believed to be angry that Clattenburg had refused to penalise Burnley full-back Jon Flanagan, who escaped punishment after appearing to catch Matteo Darmian's trailing leg on the edge of the penalty area just before half-time.
Asked about the sending off incident, Faria said: "I just want to say it was fantastic work from the referee."
Faria refused to confirm why Mourinho had been sent to the stand, saying: "I don't know and I don't think it is really important.
"I think what is important is what the referee will write in his report. I can't give you more details."
Despite his dismissal, Mourinho was able to communicate with Faria via written messages passed down by another member of his coaching staff, but his notes weren't enough to stop United's winless run in the league extending to a fourth match.
"Normally we define situations according to the difficulties of the game. Sometimes a detail is important," Faria said.
"The team did a fantastic work from the first second of the match. We were dominant with 11 men, and we were dominant with 10.
"We fought from the first minute. We showed fantastic mentality especially after a game in the middle of the week.
"With this mentality and approach, I think we need to wait for better days ahead. I believe better days will come."
Burnley secured their first away point of the season largely thanks to a superb goalkeeping performance from Tom Heaton.
The former Manchester United youth keeper made a series of magnificent saves, denying Jesse Lingard, Paul Pogba and Zlatan Ibrahimovic among others.
Burnley manager Sean Dyche saluted Heaton's display and: "I think Tom Heaton was superb. He is in very good form.
"We kept him so quiet last year that I think he has been saving it up."
Heaton's best save was a block from a stinging Ibrahimovic volley, although Dyche was wary of giving the goalkeeper too much praise.
"He just spread himself. Keepers get hit in the face all the time. It's his job," he said.
Dyche admitted he had not realised that Mourinho had been sent off, but complimented United on continuing to attack so positively after Herrera's dismissal.
"I thought Manchester United were first class. They opened us up, they pressed and they probed," Dyche said.
"Massive credit should go to them because they never stopped. I'm pleased that we managed to deal with that."