Individual mistakes and a lack of collective cohesion saw the hosts take a 3-1 lead but Diogo Jota’s 89th-minute strike, after Cristian Casseres’ own goal had got them back into the game, set up a dramatic conclusion.
In the seventh and final minute of added time 20-year-old centre-back Jarell Quansah thought he had equalised but after a long delay referee Georgi Kabakov was advised to go to the pitchside monitor and he ruled Alexis Mac Allister had handled the ball, even though it had initially bounced up off his chest very early in the move for the goal.
“I only saw the video back now and for me it’s not a handball – but how can I decide that?” said Klopp.
“Actually, I am a bit more concerned about (the fact that) I would have loved us to have played better, to be honest. That’s my main issue tonight.
“In the end, we were intense, we threw everything in, but the problem is in a football game you have to make the decisive things in the right moment to do them right.”
Liverpool’s problem was a side registering nine changes from Sunday’s draw at Luton never found any rhythm or structure and opponents who were hammered 5-1 at Anfield a fortnight ago took full advantage.
They were not helped by Kostas Tsimikas’ error dawdling in possession costing them the important opening goal to Aron Donnum.
“We cannot concede the goals we conceded again,” added Klopp.
“The first goal can happen, but then it happened in the second half with similar situations: we were completely open, last line too deep, counter-attack.
“They scored five goals, two disallowed, and that is obviously then not good. Yes, the result is the opposite of good, but the performance was just not good enough.
“It was well deserved to lose because they won pretty much all the decisive battles. We had too many situations where we should have won the ball but we didn’t.
“On top of that we gave the ball away easily at least twice – one was a goal, the other I am not sure if it was an allowed goal or a disallowed goal.
“Defending-wise it was just not good enough.”
Defeat ends a three-match winning run and although Liverpool remain top of the group their advantage has been cut to two points.
They also missed out on guaranteeing top spot early and therefore also skipping the additional play-off round in the knockout phase after LASK’s victory over Union Saint-Gilloise meant victory would have given them an unassailable lead.
The consequences of that are if Toulouse win their next game against Union the race to top the group will go down to the final round, and with Liverpool’s trip to Belgium coming immediately before the Premier League visit of arch-rivals Manchester United Klopp would have been hoping that fixture was a dead rubber to allow him to rest players.
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