The Japan captain struggled in the 3-2 loss to Toulouse on Thursday night, being hooked at half-time after picking up an early yellow card, which prompted concerns heading into the weekend.
Though Endo was far from the best on the field as Liverpool beat Brentford 3-0, he was significantly improved on midweek, in what Klopp described as a “tricky” test.
“Top, top, top. He saved our life in many moments,” was the manager’s verdict, speaking to BBC Sport.
“It was really important that he was super disciplined all the time.
“One header at the far-post area was a massive one, if that ball comes back into the box I don’t know how we’d deal with that.
“So many good moments, and then it’s just difficult, you only get so often on the ball, the wind makes it really difficult and they press, they never stop.
“So there are a few tricky moments, but he was really, really good.”
There had been debate over whether Endo should have been sent off for a 50-50 challenge with Brentford captain Christian Norgaard.
Thankfully, common sense prevailed after a long VAR check, with the 30-year-old escaping punishment, though in his post-match press conference, Thomas Frank argued, given recent examples, that it should have been a red.
“Even with VAR, I think a situation like this shouldn’t be a red card – should not be a red card,” Frank stressed.
“But with the slow image we get today, you will see a clear foot on the leg and you will see four bloody marks on Christian’s leg, then that is definitely some contact and it must be with some excessive force.
“So he definitely went over the ball with enough force to do that.
“Then you have similar against Newcastle from ourselves a couple years ago and this one today.
“With that in mind, then it’s a red card.”