Marshall was hurt by Green several times during a bruising encounter but felt she did enough to win.
The decision went against her, with two of the three judges scoring the contest in the American’s favour.
Marshall revealed she had concerns before the fight about all three judges being from the United States.
“It was flagged up the day before in the rules meeting,” she added.
“My manager (Mick Hennessy) wasn’t happy about it and he was told ‘Look, don’t worry, it’s live on Netflix and the last thing we want is controversy’.
“I feel like I was very hard done by. I’m going to America, we’ve got three American judges and I’m fighting an American. I’m gutted. But look, it’s boxing.
“I’m my own worst critic and I’ve watched it back a couple of times, and even being generous I still have her two rounds down.”
The defeat was a major disappointment for Marshall, who has also competed in mixed martial arts.
But she insists she has no intention of quitting boxing.
She said: “I remember my first amateur coach saying to me ‘You will wake up one day and you just won’t want to do it any more’.
“But this is the train I’m on at the minute. It hasn’t stopped yet.”