Xherdan Shaqiri was handed a rare start by Klopp, his first in the Premier League this season.
And Klopp insisted the Switzerland star was ready after several fitness problems.
“Shaq is in really good shape, showed a good performance last game, he’s good in training, he’s now getting rhythm step by step,” Klopp added.
“He was a long time out, with little things only but he was out, and now he’s, for a long time already, in training and shows it every day that he’s ready to go. So we let him go!”
Meanwhile, United boss Ole Gunnar Solskjaer explained his team selection ahead of the match.