Liverpool boss Brendan Rodgers accused his players of laziness after Thursday's 3-2 Europa League Group A defeat to Udinese at Anfield.
The Reds had gone 1-0 up in the first half thanks to Jonjo Shelvey's 23rd-minute strike, but the visitors' captain and talisman Antonio Di Natale levelled in the opening minute of the second period.
The home crowd were then stunned as a Sebastian Coates own-goal and Giovanni Pasquale's 72nd-minute finish from Di Natale's tee-up put Udinese firmly in the driving seat.
Luis Suarez's swiftly replied with a delightful effort direct from a free-kick, but it proved only a consolation as the Italian side made off with all three points, leaving Rodgers fuming about his team's concentration levels.
"It was very frustrating," Rodgers said.
"It was a game where I felt we were the much better side, but we lost our concentration at the beginning of the second half and I thought we'd moved on from that to be honest.
"I thought we were just lazy - that is the easiest way to describe it.
"Just lazy in our play and loose and sloppy. It is as simple as that.
"In that opening period (of the second half) we didn't do what I call the dirty bit.
"In the first half we earned the right (to be in front) - we pressed the ball, got tight and then showed our quality with the ball.
"But at the beginning of the second half we didn't do that, and before we knew it, we were 3-1 behind."
He added: "We had scored and had total control in the first half. There were a couple of little moments, but I thought some of our play was very good and we deservedly were in the lead.
"But then we were so loose at the beginning of the second half it was frightening and our concentration was very poor.
"Then before we knew it we were 3-1 down and chasing the game.
"The last 20 minutes were very good, but it was too late by then - you have got to be in control and make sure that your domination and quality keeps you in front. Unfortunately we didn't do that."
Rodgers had highlighted the threat posed by Di Natale in the build-up to the game and, when asked about the inspirational performance the 34-year-old, the Liverpool manager said: "The guy has qualities, there is no getting away from it.
"It was a very good finish for the first goal. With the third I think we gave him a wee bit too much time, but he is a quality player.
"But I'll always only concentrate on my own players and where they can improve and be better.
"They give me and the team everything, but at critical moments of the game - in particular at the start of the second half - we needed to be solid and tight, and we gave away three goals."
Di Natale was back in the Udinese team after being axed from the squad for last weekend's Serie A draw with Genoa by coach Francesco Guidolin as punishment following a dressing-room outburst.
Asked about Di Natale after tonight's game, Guidolin said: "We know he is a wonderful player, an outstanding player - I have said this time and time again.
"And in any case, this Di Natale issue is something we thought was over a while ago.
"What I really liked about tonight was my team's reaction in the second half. I tried to give my best during half-time in the dressing room to coax them along.
"I'd like to dedicate this victory to my kids who were here and of course to all the Udinese fans who made it over here."
Liverpool are now third in Group A after two fixtures, on three points, one point behind Udinese and leaders Anzhi Makhachkala.