Arsenal eased past Lille, Barcelona came from behind to beat Galatasaray and Sporting CP triumphed at Lens as all three teams made it two victories from two.
Barça extended their winning start to the campaign with an impressive comeback victory in Istanbul.
Aleksei Batrakov put the hosts in front against the run of play via a deflected effort, but João Cancelo levelled with a smart finish shortly before half-time.
Two goals in just over three minutes soon after the interval put Hansi Flick’s men in control, Lamine Yamal setting up both Fermin López’s precise header and teeing up Anthony Gordon to net from close range. Substitute Karim Adeyemi added a stylish fourth with a crisp strike midway through the second period.
Substitute Bukayo Saka’s goal and assist helped Arsenal reach six points with victory in London.
Bruno Guimarães went closest as Lille defended resolutely before half-time, visiting goalkeeper Berke Özer parrying the midfielder’s shot and reacting rapidly to claw the rebound away from Viktor Gyökeres.
Jurriën Timber’s neat turn and chip from a tight angle broke the deadlock 19 minutes after the restart, Saka then coming on to cross for Eberechi Eze’s strike and slot in a Kai Havertz pass.
Denis Suárez became Sporting CP’s outright all-time top scorer in the modern competition as his side stayed perfect.
After a clever finish for his seventh Champions League goal, Suárez had a shot turned around a post by Robin Risser before Franjo Ivanović struck the woodwork from distance for Lens.
Visiting goalkeeper Kaique Pereira tipped Amadou Haidara’s long-range effort over the bar during the second half, but Issa Doumbia sealed victory by coolly slotting in from Silas Andersen’s superb through ball.