Sir Alex Ferguson and Kenny Dalglish were both present at Anfield as Liverpool beat Manchester United 2-0 on Thursday night.
There are no prizes for guessing exactly which of the two was happier on Merseyside...
After the German was appointed earlier this season, Ferguson's reaction was telling.
The Scot was quoted as saying by Sky Sports: "Strong personality, very strong, very stubborn, determined and his performances, and his career at Dortmund was a stellar rise to the top and I think he'll do very well.
"I don't like saying that, being Liverpool, because I'm worried about it but, no, he'll do well."
Liverpool fans, of course, will now love reading those quotes even more than they originally did.
Ferguson was on hand to see for himself Klopp putting to practice exactly what the former Manchester United boss envisaged.
Yes, Manchester United were poor. But Liverpool were good - and could have won by several goals without even being at their best.
The improvement under Klopp so far has been marked. No one is getting carried away but things are certainly looking up.