The Reds were trailing to Will Smallbone’s added-time goal after a misunderstanding between Virgil van Dijk and goalkeeper Alisson.
Slot – who was watching from the Main Stand as he was serving the last game of his touchline suspension – moved quickly to rectify the situation.
Having issued his team with an order to increase the tempo, he made a triple substitution with Harvey Elliott, Andy Robertson and Alexis Mac Allister.
“I didn’t give them compliments at half-time, I can tell you,” said Slot. “Maybe I can tell you it was because I was sitting up there instead of on the line.
"When you watch a game from there you always feel that ‘Ah, even I can play in this game’ but when you are on the line, there is more tempo.
“I don’t think I was wrong if I said at half-time that the energy levels were far, far, far too low. That had to change and that is why we made three substitutions.
"Apart from energy to bring in quality. Nine out of 10 times when you take three out, the other eight are like, something else should happen.
“That was the only thing I could come up with at half-time to create something different for the second half.”
Within the space of five minutes, Darwin Nunez and Mohamed Salah, with the first of two penalties, had turned things around on Saturday afternoon.
Salah, who blasted home his second from the spot in the 88th minute, said in a post-match television interview Slot’s “head was going for us”.
Wednesday’s midweek exertions against Paris St Germain obviously took their toll, but Slot said he was not concerned by the European hangover.
“I know these players can come up with completely different energy levels than they did in the first half,” the Dutchman added.
“It was the first time this season I saw this tempo. When I look at the game against PSG, we have to go one step up in terms of intensity.
"Compared to the game today, we need to go five, six, seven steps up in terms of intensity if we want to have any chance of reaching the next round.”