City’s backline were all over the place at the Etihad Stadium as Jamie Vardy and company run them ragged to move top of the table.
Kyle Walker, Eric Garcia and Bernard Mendy all conceded penalties as Manchester City lost at home by five goals for the first time in 17 years.
Richards was unimpressed by what he saw from City’s highly expensive rearguard and has urged them to step up.
"You can’t say they are not good enough,” the former City defender told Sky Sports.
“[Kyle] Walker has been first choice for England for years, though in this system it’s probably a fair comment.
“[But] the problem is, £50 million for [Benjamin] Mendy, £50m for Walker, £50m for [John] Stones, £60m for [Joao] Cancelo, Now Ruben Dias, another talked-about £55m.
"If you’re going to pay £50m for defenders you have got to defend better than that.
"But, for me, Man City defenders are just reactive, rather than proactive.
“All of them are thinking about going forward rather than holding their position.”
Guardiola is on the verge of completing a deal for Benfica defender Ruben Dias in the coming days to tighten up his defense.
City travel to newly promoted Leeds United in their next Premier League game this weekend.
