In the 38th minute of the highly-anticipated clash, De Rossi tried to break up some intricate play by intercepting Andres Iniesta's short pass to Lionel Messi.
However, in doing so, he inadvertently turned the ball into his own net in spectacular fashion.
Unfortunately for Roma, however, the Italian veteran didn't score the only own goal of the game.
Barcelona's second arrived through a 55th-minute goal from Roma's Kostas Manolas, before Gerard Pique got in on the goalscoring fun four minutes later to put the hosts 3-0 up.
Former Manchester City striker Edin Dzeko scored an away goal in the 80th minute, but Luis Suarez completed the rout three minutes from time with a left-footed strike from close range.
After the game, Roma manager Eusebio Di Francesco felt the scoreline was tough on his side and didn't reflect the Serie A club's battling performance.
He told reporters: "I think the result is too harsh given our performance, considering who we were up against.
"We made some small mistakes inside our area and were a bit slow dealing with some situations. It's a pity, but we didn't do ourselves justice. We needed to be a bit more clinical because you don't get many chances against Barcelona."
See also...
Watch: The various in-stadium reactions to Cristiano Ronaldo's goal against Juventus
David James fires back at Dimitar Berbatov after "worst wannabe coach" jibe
'Did I say no to Liverpool last summer? Yes, I did. But I'll be very clear: if this offer had come at the end of August, just before the end of the transfer window, I would have accepted it' Reds target admits he turned down Arne Slot's project
Manchester City ready to sell Phil Foden, in shock transfer listing: report
