The German manager also said that selling striker Christian Benteke to the Eagles in the summer for £27 million "made sense," despite the Belgian's good form at the start of the new term.
Ferguson, who retired as United boss in 2013 after 26 years in charge before becoming a club director, recently praised Klopp's work since his 2015 appointment at Liverpool and conceded the Reds are title contenders, per the Telegraph.
Speaking in his press conference ahead of Liverpool's trip to Selhurst Park, Klopp revealed his regard for the Scot, per the Liverpool Echo's James Pearce:
Liverpool will come up against Benteke for the first time since the 25-year-old departed Anfield after just a season at the club on Saturday.
Given Klopp's style of play, the Belgium international never really fit into the Liverpool team, but he has had a good start to his Palace career, netting three goals in seven Premier League appearances in 2016-17.
Klopp said Liverpool always knew Benteke was a quality player, but it still was a good move to sell him, per Joe Mewis in the Mirror:
It’s no surprise. We knew about his qualities. Every player needs the space to develop and show things.
The move made sense. Palace bought the player. In the last year he always showed his qualities, especially good at heading.
We had to make decisions. I’m always honest. My door is always open. The agreement we have is work hard.
Liverpool have lost three of their last four Premier League matches against Palace, but they won the corresponding fixture last term 2-1 at Selhurst Park.
Per Liverpool's Twitter feed, Klopp labelled Alan Pardew's side a "really tough and strong opponent."
Despite being the away team, Liverpool will still be considered by many to be favourites for Saturday's clash in south London as they are unbeaten in all competitions since August and are tied on points with top-of-the-table Manchester City.
Per ESPN FC's Ben Dinnery, Klopp's main fitness concern is James Milner, who fell ill earlier in the week and who may have to be replaced at left-back by Alberto Moreno if he does not recover in time:
Palace will be looking to get back to winning ways having picked up just a point from their last three Premier League matches, but it would be something of an upset if the hosts were to better Liverpool at Selhurst Park on Saturday.