The Egypt international missed a hat-trick of relatively straightforward chances before rolling home a shot from the tightest of angles with his weaker right foot in the 2-0 Champions League victory in Austria.
It was Liverpool’s second of the night and guaranteed they would finish as Group E winners, but even then Salah had a couple more opportunities to add to his tally.
Despite having the most frustrating opening 58 minutes of his Liverpool career, the forward, who became only the second player at the club to score 20 goals in Europe’s elite competition after Steven Gerrard (30), never allowed it to affect him and Henderson said that was testament to the player.
“I can’t believe he scored that second one from the angle he was at, it was a magnificent finish,” the Reds captain told the PA news agency.
“He would probably have been wanting a couple more with the chances he had but he kept going, kept plugging away and was a threat all night really.
“You are going to get chances and are going to miss chances, that’s part of football.
“But he kept going, that’s the most important thing. The goal is a great run and a magnificent finish and he was dangerous all night.”
Liverpool took qualification for the last 16 to the final game for the third successive season – in the previous two they have gone on to reach the final, winning the trophy for a sixth time in June – and Salzburg provided a real test in the first half.
But Liverpool weathered that storm and demonstrated their professionalism with a clinical performance after the break.
“We’ve had a lot of experience in the Champions League, it’s a tough competition and there are so many good teams,” added Henderson.
“It has gone to the last game the last few years and we’ve managed to come out on top, which is important. That’s just the way it is.
“We’ve dealt with it really well, we just have to do the same in the knockout stages.
“They started quick like we knew they would but overall we deserved the win, kept defending well as a team throughout the game and a clean sheet was important.
“We scored some good goals and probably should have had some more to be honest.
“We had some good last-ditch tackles, Ali (Alisson Becker) made a good couple of saves as well which is important, but we knew we would have to do that, especially coming away from home here, we knew it would be difficult.
“We kept working and second half we played some great football, created some good chances and it could have been more in the end.”