Nick Cushing’s side have started the campaign superbly, winning our opening four games in style, scoring 15 goals and conceding just once.
Mannion, who joined from Birmingham in the summer, believes she has already improved since arriving for pre-season training - and says she is glad she no longer has to come up against us.
“I’m being pushed very hard physically, the hardest in my career,” she said.
“I’ve been places I’ve never been before on the training pitch and in the gym.
“I wouldn’t wanna be playing city in the 70th minute because we can push so hard.
“I’ve always thought I was a very physical game, but here everyone is a superstar. I’ve had to dig deep to earn respect and earn my place.
“If you look at the squad list, it speaks to itself. You don’t need me to sit here and tell you how hard it is to play against these forwards, or what it’s like to play alongside Steph Houghton - players of international calibre.
“When going into last 20 minutes, quality and consistency shines.
“As I say, I wouldn’t like to be playing against us.”
City face Swiss outfit Lugano on Wednesday in the UEFA Women’s Champions League, with Cushing’s side 7-1 up from the away leg.
It was a superb performance in Lugano, particularly in the second half which saw City dominate, both technically and physically.
It’s a commanding lead we take into Wednesday night’s tie, but Mannion says continuing to play the kind of open, attractive football we’ve managed in our other games this season should be a priority.
“We focus on performance,” she said. “We are in control of the story we tell.
“We want to put things we’ve practiced out on the pitch.
“When you’re playing a team like this, the sessions can be more mentally taxing than the games.
“So it’s not just about the game day, it’s about living it on the training field and bringing a positive vibe to the camp.”