"They are brilliant, on and off the field. Their mindset is amazing," Greenwood told ESPN Brazil.
"They are champions. It ends up bringing confidence and, more importantly, they are incredible people."
One of the biggest challenges for players coming from the United States is adapting to the different style of play but Greenwood said her teammates hadn't faced such issues.
"It must be very different for them," she added.
"Here in England we love the game, we are fanatics and there are also tactical, speed issues. The fans can be more 'difficult' but they are adapting easily."
Greenwood, who joined City from Lyon in September on a three-year contract, said the competitiveness of the WSL attracts players to it.
"The games here are on another level, in the sense that you don't go on the pitch knowing that you are going to win," Greenwood said.
"At Lyon, if you lose a few games it is disastrous, it doesn't happen. Unless it's against Paris Saint-Germain or something in Europe.
"That is why, in England, the issue is competitiveness, it ends up attracting more athletes here."