There were surreal scenes at last night's Liverpool friendly against Huddersfield.
Play was briefly halted by a drone which appeared over the pitch before, even more bizarrely, Klopp sent on reserve goalkeeper Shamal George to play up front when Lucas went off injured after all outfield substitutes had been used.
He almost set up Lazar Markovic with his first touch.
Sadio Mane, a £30m signing from Southampton, was lively, having a goal harshly ruled out for a foul on Joel Coleman after a misplaced backpass and then inducing the goalkeeper to foul him for a penalty which Philippe Coutinho subsequently missed.
But it was midfielder Marko Grujic, only just turned 20, who impressed the most in central midfield and scored for the second successive pre-season game, rifling home Mane's cross after the forward had been sent free down the right by Dejan Lovren.
When Liverpool won an 89th-minute penalty the away fans chanted for George to take it but Alberto Moreno assumed responsibility and scored.
"The game was difficult. The first half we should have scored more," added Klopp.
"We missed a penalty and had a few big chances and played some wonderful combinations so it was really good.
"But I was not too happy with the concentration level in the first 20 minutes.
"I said to the boys it was not bad but if we trust a little bit too much in our skills than a team performance it is not the best decision to make."
On the decision not to allow George to take the penalty, Klopp said: "Even though it doesn't look like it all the time these games are quite serious - we don't want to make joke games.
"It is nice when the crowd calls it in but at 1-0 in no game in the world should you make a 'funny' decision.
"If it is 4-0 or 5-0 you can think about it but even then it is a lack of respect for the opponent."
When asked about joe Allen, Klopp admits he is an admirer of the player but he refused to be drawn on the future of the midfielder.
It is understood that the club have accepted a £13m bid from Stoke for the Wales international.
That means the decision now lies with Allen, who is in the last year of his contract at Anfield and is keen to have more pitch time having been reduced to mainly Europa League appearances last season.
"There is nothing about this and all the transfer rumours," said Klopp after a 2-0 friendly win over Huddersfield.
"We cannot comment because we couldn't do anything else all day so we shouldn't start with this.
"I feel good (about Joe). I like the guy and I really think he is a wonderful football player.
"I knew this before the European Championships, I saw it during the Euros and I know it now.
"I have said all I can say about this. It is all about respecting contracts, negotiating or not - whatever - and making a transfer or not.
"But it is nothing to discuss in public but I've not seen him since the middle of May in Basle (when Liverpool lost the Europa League final to Sevilla)."
Defender Jon Flanagan was left out of the squad to consider whether he wants to join Burnley on a season-long loan while Lucas Leiva, who is a target for Galatasaray, limped off in the second half against the Terriers with a hamstring problem.
He will have a scan on Thursday but it is likely to mean he will miss the tour to the United States, which the squad fly out to in the early hours.