Liverpool and Manchester City will travel to Wembley to battle for a place in the final of the competition, just a week on from a 2-2 Premier League draw at the Etihad.
England's latest blockbuster rivalry has transfixed global audiences, as the opposing managers look for an edge in the battle for football's top honours.
Last time out, that edge was found by Guardiola, who changed City's set up to record a number of glorious breakaway chances against Liverpool's high defensive line.
Klopp noted the switch post-match saying a lack of pressing allowed City to play high balls 'just like it was a set piece'.
And Babel, who managed to catch some of the game, despite starring in the Istanbul derby between Galatasaray and Fenerbahce, noticed the effect.
"The first 30 minutes was not good from Liverpool's side," he told talkSPORT. "But they didn't lose which is better."
Klopp explained 'City were a bit more direct than they usually are' as they racked up one of their best showings in the fixture, which marks a contrast to when Babel faced both managers while playing with Fulham in 2019.
The Dutch forward said: "The main differences were in my opinion, Klopp's playing style. Even though he, of course, wants to play good football with Liverpool, at times it was very direct.
"Three passes and they were in front of the goal, with Guardiola he was clearly like 'OK no, I want you guys to play and pass and with passing reach the goal and try to score'.
"You could see at that time it was two different types of styles and opponents and it was definitely difficult to compete with as a Fulham side at the time."
Guardiola has since opted to fight fire with fire though, according to Klopp, who will have to be wary when they meet again in the FA Cup.
The rival coaches joined the league in nine months apart across 2015 and 2016, taking over clubs in very different situations.
Babel agrees with claims that Klopp has had to overcome far more challenges than Guardiola when it comes to squad rebuild and finances, but insists money isn't everything.
He explained: "[Klopp] of course also has had his budget but I don't think you can completely compare it to what City have been able to spend over the past decade.
"Also knowing the moment where he stepped in, where Liverpool was at that time, how he was able to change that in a relatively very short time.
"It's not a given that a good coach or any coach can naturally change a team, we see now Man United struggling for some time now and they have had a lot of good coaches trying it so it's a combination of a little bit of luck and support to be able to turn things around."
Babel has experienced Klopp in two different leagues, facing his Borussia Dortmund in 2011 with Hoffenheim and then his Champions League-winning Liverpool squad as a Fulham player in 2019.
The 35-year-old Galatasaray forward is delighted to see his former club doing so well, but isn't surprised by Klopp's success, having witnessed his breakthrough in Germany.
Asked if he could tell how good Klopp was going to be over a decade ago, Babel said: "Yeah, the Dortmund side was already playing great football.
"He had great players in his team and Dortmund was already at that time a very tough opponent to play against, they were competing already with Bayern Munich."
Klopp's Dortmund were the last team to beat Bayern to the title before their current run of nine consecutive championships began, but his spell in black and yellow coincided with Guardiola's arrival in Munich.
The pair are back on a level footing now though, and are likely to keep on fighting for far longer as they desperately search for an edge in football's most enthralling new rivalry.