Liverpool won the Champions League clash 2-0 on Wednesday night.
Koeman said: “The quality of Gerrard was outstanding, it was an excellent midfield performance and was something we could not match.”
He added: “We did not do too badly, we did not give away possession but our build-up play from the back let us down.
“We have dangerous players up front but if we do not get the ball to them properly, we will not score goals.
“A lot of our play was really sloppy, if you do that you do not create much up front.”