The Reds ended a run of four consecutive defeats with a commanding display in Germany, coming from behind after Rasmus Kristensen had fired Frankfurt ahead.
Hugo Ekitike levelled against his former club, before goals from Virgil van Dijk, Ibrahima Konate, Cody Gakpo and Dominik Szoboszlai sealed a morale-boosting win for the Premier League side.
"It was a very good performance," said Slot. "We created chances before conceding, which has been the case in recent weeks, but this time we took them. Going 3-1 up before half-time made a huge difference. I've said many times how important set-pieces are, and tonight we scored two from them, that balance is so crucial."
Slot also praised his players for pressing effectively, something he felt had been missing in previous games. "We got energy from pressing them. In recent matches we couldn't do that because the ball was often in the air. Today it was on the ground, and we were able to play our game," he added.
The Dutchman was particularly impressed with Ekitike, who scored his first Champions League goal for Liverpool since joining from Frankfurt for sixty-nine million pounds in the summer. "The first goal was special," said Slot. "You could see his pace and confidence. We've created many chances in the last few weeks but not always finished them, so it was great to see him take his opportunity."
However, there was some concern for striker Alexander Isak, who was substituted at half-time with a groin problem. "Alex felt his groin a little bit, which is unfortunate," Slot confirmed. "It's always a difficult balance with players returning from long injuries. He's played twice in three days, so we'll assess him and hope for the best."
Liverpool's emphatic win extended their unbeaten run against German opposition to fifteen matches (twelve wins and three draws), dating back to 2002. The result also piled pressure on Frankfurt, who remain without a win in five meetings against Premier League clubs.
Slot will now hope this victory marks a turning point as Liverpool look to rebuild momentum in both domestic and European competition.
Manchester United continued their strong Premier League surge under interim manager Michael Carrick with a controlled 2-0 victory over Tottenham Hotspur at Old Trafford.
Borussia Dortmund captain Emre Can has suffered a fresh injury setback that has delayed his expected return to action, dealing another defensive blow to head coach Niko Kovac ahead of Saturday's Bundesliga trip to VfL Wolfsburg.
Daniel Farke praised a "massive win" after Leeds United strengthened their Premier League survival push with a deserved 3-1 victory over Nottingham Forest at Elland Road on Friday night.
Manchester City boss Pep Guardiola has hailed Erling Haaland as the "best striker in the world" despite the Norwegian's dip in form, but refused to confirm if he will start Sunday's crucial clash with Liverpool.
