UEFA swiftly barred all Russian teams from competitions last year in response to Moscow's offensive in Ukraine, but eased the ban by readmitting Russia's national under-17 team on Tuesday.
Felix shone for the Spanish champions on a stroll on a warm night in the Catalan capital, helped on their way by an own goal, with Robert Lewandowski and Gavi also scoring.
The French champions had dominated the first half without overly troubling the Dortmund defence, but they went ahead four minutes after the break when Kylian Mbappe scored a spot-kick awarded for a Niklas Suele handball.
Union Berlin make their Champions League debut at European royalty Real Madrid on Tuesday just four years after a first ever promotion to the German Bundesliga.
Manchester City begin their defence of the Champions League on Tuesday when the group stage kicks off in the last season in its current format as Europe's elite club competition gets ready for a radical change.
Manchester United and Bayern Munich will face each other in UEFA Champions League Group A while Borussia Dortmund, AC Milan, Newcastle United and PSG were put in a highly-competitive Group F.
After several near misses in recent years, Pep Guardiola's side won the trophy for the first time when they defeated Inter Milan 1-0 in last season's final in Istanbul in June.
A Greek football fan was fatally stabbed during a brawl near Athens between rival fans, leading UEFA to postponed Tuesday's match between Greek hosts AEK Athens and Croatian club Dinamo Zagreb
Lionel Messi has called his start at former club Paris Saint-Germain "very tough", dubbing two successive failed Champions League bids a "massive disappointment".
It is the second Champions League final held at the Ataturk Olympic Stadium, situated on the European side of the Bosphorus, 25 kilometres from central Istanbul.