Virgil van Dijk acknowledged Liverpool were at fault for their mistakes in their Champions League loss to Real Madrid but argued they cannot expect to perform like "robots".

Liverpool blew a two-goal lead at Anfield, slumping to a 5-2 loss in the first leg of their last-16 tie against the holders.

Amid a difficult season for Jurgen Klopp's side, their collapse against Madrid made for a chastening rematch of last year's final, which finished 1-0 to Los Blancos in Paris.

Van Dijk did not dispute another off-color performance yet the center-back stressed errors are to be expected when players are only human.

"[Across] the whole of the Champions League, there are quality players all over teams," he told reporters. "They can punish you, and can punish the mistakes that you make.

"That's what they did in the second half, and it is pretty clear to see. [There were] mistakes that we shouldn't make, but it happens in football.

"We're not robots, sometimes mistakes happen. That is the case. The only thing we can do is learn from it and focus on the next one to ensure it doesn't happen [again]."

After goals from Darwin Nunez and Mohamed Salah had given them a two-goal cushion inside the opening 15 minutes, Liverpool seemed on course for a memorable Anfield triumph.

Yet their defensive frailties came to the fore as Vinicius Junior curled in a supreme finish before pouncing on Alisson's mistake to restore parity.

Eder Militao put Madrid ahead early in the second half before Karim Benzema's double left the hosts with a mountain to climb in the return leg next month.

Klopp was less than impressed with cheap concessions but did feel his side's first-half performance was among the best they have delivered this campaign.

"We gave all five goals away," he said in his post-match press conference. 

"All five. We could have done better there [but] in our situation where we are, it is really important we that see positive steps.

"I think the first half, aside from the two goals we conceded, was the best we've played [across] the whole season.

"The second half obviously was the game Real Madrid wanted to play, and that's how we came to the result."