It was a dead certain penalty to me.
Here's what the laws say
“Handling the ball involves a deliberate act of a player making contact with the ball with his hand or arm. The referee must take the following into consideration:
- The movement of the hand towards the ball (not the ball towards the hand)
- The distance between the opponent and the ball (unexpected ball)
- The position of the hand does not necessarily mean that there is an infringement
- Touching the ball with an object held in the hand (clothing, shinguard, etc) counts as an infringement
Hitting the ball with a thrown object (boot, shinguard, etc) counts as an infringement.”
Look at the replays, he guy jumped and the ball hit an outstretched arm as he was turning. Nowhere near deliberate. Even Klopp says it was a lucky call.