Deutsche Welle reports a judgement was filed in Clapton's favor earlier this week at a court in the Düsseldorf area of Germany ... where he'd sued this 55-year-old widow, who says her late husband bought the album years ago at a record store -- arguing she didn't know it was fake or infringing on his copyright.

The woman was reportedly trying to sell it on eBay for less than $12 -- something Eric and his team apparently caught wind of somehow, and decided to fight it tooth and nail.

Word is, they'd reached out this lady ... demanding she take down her eBay sale -- but word is, she told Eric and co. to kick rocks and to stop harassing her. The Guardian reports she even said if they were that bothered with the $11 sale, then go ahead and sue her.

Well, sue her he did ... and after her arguments of ignorance fell flat with the court following an appeal -- issuing an injunction preventing her from hawking the thing. She's also gotta pay the legal fees of both parties, which reports say amounts to about $3,800. If she keeps it up on eBay, she could be fine hundreds of thousands ... or even go to prison for half a year.

Clapton's team told the Guardian, "Germany is a country where sales of bootleg and counterfeit CDs are rife, which damages the industry and customers with poor quality and misleading recordings. Along with a number of other major artists and record companies, over a number of years Eric Clapton has, through German lawyers, successfully pursued hundreds of bootleg cases in the German courts under routine German copyright procedures."