The Brazilian were controlling the sport for Liverpool sooner than he used to be changed by Welsh teenager Ben Woodburn.
But with Coutinho gazing from the stands, the hosts grew into the sport and Shinji Okazaki broke the impasse for Leicester on 65 mins with a deflected end.
Despite Liverpool having a look a lot the simpler facet within the first part, Leicester have been quickly within the ascendancy.
Islam Slimani doubled the Foxes lead with an impressive shot from 25 yards out, leaving Klopp livid at the bench.
Coutinho had had his possibilities to get at the scoresheet at the King Power Stadium, two times checking out Foxes goalkeeper Ben Hamer.
He put huge an Andrew Robertson go sooner than being hooked at the smash.