The holders booked their place in the last 16 as Group E winners courtesy of Tuesday's battling victory in Austria, Naby Keita and Salah scoring in the space of 100 second-half seconds.
Salah's right-footed effort after rounding goalkeeper Cican Stankovic came from an extremely tight angle as the Egypt international netted for the second straight game.
Asked how Salah had managed to do it, Klopp said to BT Sport: "I have no idea! No idea.
How the hell does Mo Salah miss sitters then hit a goal from this angle? pic.twitter.com/Dm5W8DRkCL— Brody Logan (@BrodyLogan) December 10, 2019
"To be honest with his quality, with how he well did in one of or two of the other situations, I have no clue [with those] as well. Just great, that's how it is.
"In a perfect night everyone can score goals especially with the quality of the boys. But when it looks like, 'It's not my night' and then staying on track and scoring, that is the big thing in football.
"When we had the ball and when we played calm we were immediately in front of their goal and we had sitters, pretty much.
"But we didn't score these situations. Then we scored a wonderful goal [through Keita] and then Mo, with the most difficult situation of the whole night, he scores that goal, so all good. That is what a striker has to do.
"There were so many sensational performances and showing this kind of great attitude again, I'm really happy."
Reply with an emoji to describe Mo's outrageous goal pic.twitter.com/udE3WlcR0o— Liverpool FC (@LFC) December 10, 2019
Klopp was impressed by Salzburg and thought his players had been given a stern examination, even if they could have ended up scoring many more.
The German added: "I could not have more respect for what Salzburg did here - what a team, what an effort, it was really a tough game, a tricky one.
"They started so direct, all the little things they worked for, they did so many smart things.
"But the really big chances we had obviously. They did a lot of things but we were there, we were ready to defend it. You cannot always defend it in the first moment but then we did in the last line. We had to put a proper shift in.
"It was just a very intense game and second half they [Salzburg] obviously couldn't cope with the intensity after the first half. We then scored the two goals, wonderful goals.
"In a game like this we could have scored six, seven goals which is crazy. But it's completely okay that we didn't do it - we won the game, won the group, all good."
Liverpool have won four consecutive matches in all competitions and have not been beaten since their loss in this group to Napoli back on September 17.
WE. KEEP. GOING. pic.twitter.com/TceFfavvk3— Liverpool FC (@LFC) December 10, 2019