Bothroyd was on the mark in Saturday's 3-2 defeat to City.
He said: "We definitely played against the champions. You just have to look at their bench - God knows how much it cost. They’ve got a world class squad.
"What make City the best side? The best players. But, of course, it’s more than ability, names don’t make a great team, it’s the work ethic and the ability.
"They’ve got that in abundance. They hammered United, they’ve been in top form all season, they’re scoring goals freely and generally keep it tight at the back.
"They’ve got some big strong players. A lot of experienced professionals who are strong and hungry, they want to win something."