The hosts dominated proceedings from start to finish with Antoine Semenyo, Savinho and Omar Marmoush getting the goals for the Citizens.
Speaking to Premier League website after the English topflight fixture, he acknowledged that his team failed to produce the level required to compete against the reigning champions.
"Today we have to accept that City was much better and too good for us,” Glasner said.
“If you want to get a point here you need a top performance and it was far away from a top performance. We had one of two chances but couldn't take advantage of it and that's why it was 3-0.
"We knew how they want to play but it's not so easy to defend all the time. We lost the ball too easily, the first goal you saw the quality City has when Foden has the ball and a clinical finish from Foden.
“The second goal is poor defending from us. We should have done better when we had the ball; we lost it too easily and then the pressure keeps increasing."