The Reds boss’ intention was for his players to come out of the blocks and consolidate their 2-0 first-leg lead over Villarreal to ensure passage to a third final in five seasons.
What actually happened was they had to prove their ability to react to adversity after the advantage was wiped out by debut goals in the competition from Boulaye Dia and Francis Coquelin.
The introduction of winger Luis Diaz at half-time and a tactical tweak saw the match turned on its head with three goals in 12 minutes from Fabinho, Diaz and Sadio Mane, helped by an unconvincing goalkeeping performance by goalkeeper Geronimo Rulli.
Not only was this their first European semi-final away leg win in five attempts since 1985, the 5-2 aggregate scoreline also ensured Liverpool became the first English club to reach the final of the European Cup/Champions League, FA Cup and League Cup in the same season.
Asked what the message was at half-time, Klopp said: “Play better than the first half.
“We just explained where we had to go and move smarter. There was no flexibility, nothing, so we had to mix that up and cause them some problems because with the man-orientated defending we played into their hands.”
Klopp, who in qualifying for his own fourth final equalled the record of Marcello Lippi, Sir Alex Ferguson and Carlo Ancelotti, said making a third in five years was “massive. Outstanding.”
“Before the game I told the boys I’d like to read the headline ‘Mentality monsters were in town’ – ‘Mentalidad monstrousa’ or whatever – because I wanted us to be the ones who went for the result and not defend,” he said.
“I couldn’t see that at first but the second half was. For me it was like this because of how much we impressed on them about coming back in the second half.
“With 500 games the boys played, a completely normal thing like the first half can happen but how we reacted and how it happened is special.
“I know supporters of other clubs might have been happy with the first half and that we got a ‘knock’.
“It is really difficult to reach three finals [in one season], which is probably the reason why no one did it so far but we made it happen.
“When the finals show up in our schedule we will make sure we are ready for it.”
Villarreal, last season’s Europa League champions, were trying to create history of their own by reaching a first Champions League final and while they came close, manager Unai Emery admits it was not a surprise they came up short.
“We made a huge effort in the first half and we knew that could be heavy on our legs in the second half,” he said.
“We were not quite the same team in the second half. We couldn’t find the right amount of strength. We lacked something extra.”