The Portugal defender had ended his decade stint at Real Madrid a year before his former partner cynically injured the Egyptian in Kyiv.
Liverpool faced Porto in successive seasons back in 2018 and 2019, winning away from home 5-0 and then 4-1 with Salah scoring in both games.
Pepe played in the latter fixture and will now be out for revenge - with Lionel Messi aware of the rough treatment the 38-year-old can dish out.
It was one of his particularly bad challenges on the Argentine that earned Pepe his fearsome reputation as one of football's bad-boys.
The centre-back stamped on Messi's hand during an El Clasico in 2012 but insisted it was 'unintentional', and received no punishment.
Such an excuse didn't fly when he was handed a ten-match ban three years earlier for kicking Getafe's Javier Casquero twice before striking his teammate Juan Albin in the face while verbally abusing them both.
Nor did it at the 2014 World Cup when Pepe was handed another red card for head-butting Germany's Thomas Muller.
Yet, despite his reputation, former Maritimo manager Nelo Vingada insisted the Brazilian-born footballer has been misunderstood.
He told the BBC: "He's the sweetest person in the world, very affable, but when he goes on to the field, he has a very unique identity as a player, which sometimes doesn't reflect his personality, his nature, his feelings.
"I believe he has gained a reputation based on images from one or two Real Madrid games.
"As much as we like Pepe, it doesn't hurt to recognise that those were behaviours that didn't dignify him.
"That was not Pepe. The Pepe I know is the player from the other matches - sometimes aggressive, but always within the limits of football."
Pepe himself recently unveiled his softer side by admitting that he slept in the same bed as his parents until he was 17 and left for Europe.
Speaking to Tribuna Expresso, he said: "Until I came to Portugal, at the age of 17, I slept with my mother, so imagine what it was like [laughter].
"I was already big and I slept with my parents, so I imagine my father did not like to have me there [laughs].
"This is interesting: the other day I was talking to my mother and she was telling me that I really liked to run my hand through her hair and I told her that maybe I already knew it would be too much time away from her."
Pepe is now in the twilight of a stunning career that includes three Champions League wins and European Championship glory in 2016 alongside Cristiano Ronaldo with Portugal.
But he proved his hot-headedness is still present after he sparked a 20-man brawl during a pre-season friendly against Roma this summer.
And Porto fans will be hoping the aggression that made the veteran so menacing is in full force tonight if they are to succeed in stunning Anfield.