The Spaniard was dismissed by referee Michael Oliver for two fouls on the tricky Eden Hazard after just 35 minutes.
He picked up his first yellow card for body checking the Belgian before he was shown another – and then a red – for tripping him up.
Henrikh Mkhitaryan was immediately replaced by Marouane Fellaini as Mourinho reshuffled his pack following the midfielder’s dismissal.
Speaking on the BBC at half time, Shearer hit out at Herrera for getting himself sent off, and was backed up by Gary Lineker, who was in full agreement.
“Yes for me [he should have been sent off], you can’t complain with that one at all [the first booking].
“I think he knows what he is doing there, he’s stopping Hazard.
Conte speaks before his side take on Man Utd
“And the second one, I know he hasn’t made a foul since his yellow card, but the referee is talking to them about constantly fouling Hazard.
“Stupid, he knows he is on a yellow card.”