Kenny Dalglish felt Liverpool were desperately unlucky in suffering a late 3-2 defeat to Queens Park Rangers.
Goals from Sebastian Coates and Dirk Kuyt put the Reds into the lead at Loftus Road, but Shaun Derry and Djibril Cisse drew the hosts level before Jamie Mackie scored an injury-time winner.
Dalglish conceded the next few days would be spent trying to find answers to why Liverpool let slip a two-goal lead, but felt the application of his players could not be faulted.
"I don't think anybody saw it coming," the boss told his post-match press conference. "I'm sure there was a fair bit of feeling before the game about how we'd approach it and how the players would react to qualifying for a semi-final.
"But I think the way they started the game was fantastic with the passing and the movement. The only thing that was missing was a bit of luck in front of goal.
"We came in (at half-time) at 0-0, but it could have been three or four easily.
"We started the second half and got the goal - a great goal for Seb. Then Dirk touched one in and to be fair you couldn't even see them (QPR) getting a goal.
"But maybe the luck they never got at Bolton 10 days ago, they got tonight in the last 20 minutes.
"There is not much more we can say. We need to find answers and make sure we're going to learn from it.
"For most of the game we were dominant. We were really creative, thoughtful and professional, but they've walked away with three points."
Asked if he felt the Liverpool players concentrated for 90 minutes, Dalglish said: "I think they did, yes.
"It's not a lack of concentration. You've got to give them (QPR) a bit of credit as well.
"We were so constructive in so many parts of our game tonight, but (from) a set play, a cross and then right at the death they've scored.
"We never got what we deserved, but it's a tough life I suppose."
Meanwhile, Dalglish confirmed Liverpool will need to assess the fitness of Martin Kelly and Charlie Adam after the pair picked up knocks at Loftus Road.
"It's just a kick he got on Sunday," the manager said of Kelly. "Charlie just twisted his knee a little bit, so we'll need to see how he is as well."