The Liverpool skipper felt that the Central American outfit should have had more than just Brayan Beckeles sent off as he played just 45 minutes to rest a slight groin strain.
|15/8||England are 15/8 with William Hill to win Group D at the 2014 World Cup|
A number of the Central American players made some aggressive challenges, with Brayan Beckeles sent off for two bookable offences in the second period.
And Gerrard was particularly frustrated by the fact that Emilio Izaguirre wasn't red carded for kicking the ball at a stricken Daniel Sturridge in the first half.
"I thought the refereeing was poor. They were doing stupid fouls, breaking up the play for no reason," he told ITV.
"We're frustrated but we're relieved to come out unscathed. There were some horrific challenges going on out there.
"I don't understand referees who see balls kicked into stomachs and not send them off. We're relieved to come out of it with no injuries.
"A lot of the boys are frustrated but we've got a week to go to get ready."
Gerrard was substituted at half-time in Miami to protect a slight groin strain, and he believes that the World Cup in Brazil will be much more about the squad given the extreme temperatures in South America.
"Everyone's going to be important, the conditions out there mean it won't be an 11-man tournament. These days we have better subs and a better squad."