Salah found the net from the tightest of angles at Red Bull Arena on Tuesday night to put Liverpool into a 2-0 lead that secured their place in the Champions League knockout stages.
It was a moment of genius by the Egypt international, who had earlier been off target from several promising positions, and Henderson was stunned by the skill.
“I can’t believe he scored that second one from the angle he was at, it was a magnificent finish,” said the Reds captain.
“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.