The 26-year-old came off the bench to score a 95th-minute equaliser as Liverpool drew 1-1 at Kenilworth Road. Diaz was a surprise inclusion in Klopp's squad as he continues to deal with the kidnapping of his father by armed gunmen in Colombia.
After the game Klopp told Sky Sports: "[It was] A wonderful moment but it doesn't change the situation. [The] most important thing is that his father gets released. It is wonderful he wanted to be here. That's it, for us it's a super important goal and for him very important and emotional, but that's it."
Liverpool failed to convert any of their 23 attempts before Diaz headed home, with Darwin Nunez missing an open goal. In celebrating his goal, Diaz revealed his undershirt with the message: "Freedom for papa".
"[It was a] wonderful highlight in a game with not a lot of highlights and Luis came on and scored a goal. It's really great," Klopp said to BBC Sport.
He added to Sky Sports: "He can always do that. When he is on the pitch he is always involved in special things. We knew he would be a threat, we didn't know how long he would play because he only had a few sessions with the team but that is not the most important part today. He scored the goal but we need to see some improvement in Colombia."
Next Match
Liverpool will travel to the southwest of France to face Toulouse in the Europa League on Thursday, before hosting Brentford at Anfield on Sunday.