The Magpies went down 6-1 to City away from home at the Etihad Stadium in the Premier League.
Newcastle actually took the lead in Manchester after 18 minutes when Serbia international striker Aleksandar Mitrovic found the target.
City came back strongly and scored no fewer than six goals, with Argentina international striker Sergio Aguero bagging five.
Newcastle legend Shearer was following the game, and he was far from impressed with the performance of Steve McClaren's team in the second half.
Over the course of the 90 minutes at the Etihad Stadium, hosts City had 64% of the possession, took 23 shots of which 11 were on target, and earned six corners.
Visiting Newcastle had 36% of the possession, six shots of which four were on target, and earned three corners.