The 47-year-old hailed the character of his young team as he felt they endured the rainy conditions at the Fritz-Walter-Stadion extremely well to pave the way for an emphatic win
The hosts took the lead through a Felipe Santana own-goal, but a Lucas Barrios hat-trick, along with strikes from Mario Gotze and Ivan Perisic put the basement boys to the sword, despite Pierre de Wit pulling one back straight after the break.
The victory means BVB have now equalled Bayern Munich's record points tally in a single Bundesliga season, but Klopp admits he was more enthused by the manner in how his players reacted to the rainy conditions at the Fritz-Walter-Stadion.
"It was not so easy for my players to perform in this weather, considering football is such a demanding sport," Klopp noted after the match.
"Throughout the season, we have been very good defensively, but today we were distracted easily.
"In the end though, [our display] was perfect and I am very satisfied with the outcome [of the match]."
Dortmund find themselves on 78 points with one match to go before the end of the season, having already secured the Bundesliga title last week, and just need a point against Freiburg to better the Bavarians.