Mesut Ozil guided Arsenal to a 2-0 victory over Napoli while a late Cesc Fabregas header gave Barcelona a laboured 1-0 win at 10-man Celtic in the Champions League on Tuesday.
Both teams have six points from their opening two games, as do Atletico Madrid, who beat Porto 2-1. their Turkey midfielder Arda Turan netting an 86th minute winner.
Ozil has quickly impressed since his big-money move from Real Madrid last month and he again oozed class at the Emirates as Arsenal took control of Group F by easing past a Napoli side tasting defeat for the first time under coach Rafael Benitez.
The German international opened his account for the London club with a sweet strike from the edge of the box after eight minutes.
He then set up Oliver Giroud for a second soon after in a display that left manager Arsene Wenger searching for superlatives.
Borussia Dortmund's Poland striker Robert Lewandowski scored twice in a 3-0 demolition of Olympique Marseille as did Chelsea's Brazilian Ramires to get their campaign up and running in a 4-0 win at Steaua Bucharest after a shock opening home defeat by Basel.
There was also late drama in Amsterdam with Stefano Denswil heading Ajax ahead in the last minute, only for Mario Balotelli to level with a penalty in the fourth minute of stoppage time in a 1-1 draw.
Julian Draxler's goal just after the break was enough to beat Basel and maintain Schalke 04's perfect start.
Image: Mesut Oezil of Arsenal celebrates after scoring the opening goal during UEFA Champions League Group F match between Arsenal FC and SSC Napoli at Emirates Stadium.
Photograph: Paul Gilham/Getty Images