Salah admits he had an "honest conversation" with Slot at the time, who he found "difficult" initially. However, the Egyptian eventually knuckled down and produced arguably the best season of his career under the Dutchman.
Slot recalled to BBC Sport: "I'm not so stupid that I just say this out of the blue, bam.
"And I think I'm smart enough, and I think the main thing you have to do as a manager, if you want to bring your message across... you have to do this in the right way.
"So it wasn't only that - probably I gave him 15 compliments during that conversation, and then I showed him how he did the warm-up."
Slot added: "I could even understand him thinking, 'is all of this necessary?'
"The way your message comes across, that is something where I think we as managers can make a difference, not so much maybe in our tactics because everybody has great tactics, but how you bring your tactics across - do the players believe in it?
"That is something I think where a manager can make the difference."