Dimitris Nikoloau's own goal at Barcelona makes the Olympiacos man the fifth player already this season to put through his own net against the Catalans.
Nikoloau turned Gerard Deulofeu's 18th-minute cross past keeper Silvio Proto to give Barça the lead in the LaLiga giants' 3-1 Champions League win on Wednesday.
Leo Messi and Lucas Digne then fired in second-half efforts as Ernesto Valverde's side made it three victories out of three in this year's group stage, with Nikoloau on target at the right end to pull one back for the Greeks late on.
Own goals remain Barça's second-leading scorer
Barcelona have now netted 32 times in all competitions in 2017/18, with leading marksman Messi bagging 15 of them - and own goals remaining the Blaugrana's second-most prolific scorer this term.
Barça had already benefited from own goals by Real Betis' Alin Tosca, Sporting CP's Sebastian Coates, and Girona's Aday Benítez and Gorka Iraizoz.
Luis Suárez two behind Barcelona's o.g. haul
Meanwhile, Luis Suárez is on three, with Paulinho and Denis Suárez on two each and Digne, Gerard Piqué, Sergio Busquets, Sergi Roberto and Ivan Rakitic all on one.