Milan Pavkov's first half doubled stunned the visitors and earned Red Star a memorable three points.
Degenek also revealed that Reds midfielder James Milner told him that he had never witnessed a better atmosphere.
"We played well and managed to shut them out. Pavkov scored two beautiful goals, but all the boys played really well. Now if only we could play like this every week," Degenek said.
"I think Liverpool underestimated us and consequently paid for that mistake.
"I spoke with Milner in the tunnel and he told me he'd never experienced anything like the noise coming from above the tunnel. I believe we can repeat this against Napoli."