The Reds were furious over the two pens awarded to Harry Kane and Erik Lamela.
"I still cannot believe it happened," Lovren told Sky Sports News. "I saw the two situations afterwards and I was even more surprised to be honest because on the pitch it looks different.
"Maybe you say okay first it was a penalty because he touched him, or it was not offside.
"But when you see these images it looks even worse. I just do not understand these rules.
"In this situation we need the VAR system," he added. "But we could not find it because nobody understood what was happening.
"Then when I saw what the referees were saying between each other 'did he touch or not', I don't know what he said, but then suddenly he gives a penalty.
"It cannot be like that, you need to be 100 per cent when you give a penalty in the 85th minute and in the 95th minute."