Against Bournemouth, the Toffees slipped to a second defeat in a week, after their shock EFL Cup exit against Norwich, and a first Premier League loss under boss Ronald Koeman.
Jagielka said: “We are disappointed in the way we have performed.
“We will look at the video and iron out some things we did wrong and then move onto next Friday's game against Crystal Palace.
“It is a massive game before an international break. It is important to get back to winning ways."