Arsenal produced the night's most emphatic home win in the Champions League, beating Lille 3-0 at the Emirates. After a goalless first half, the hosts scored three times in seven minutes through Jurrien Timber, Eberechi Eze and Bukayo Saka.
Barcelona also stayed perfect, coming from behind to win 4-1 at Galatasaray. The hosts led early, but Barcelona replied with four goals to take control of the match in Istanbul.
The drama of the round came at San Siro, where Club Brugge beat Inter 4-3 in a seven-goal game, helped by a hat-trick. Elsewhere, Atletico Madrid beat Manchester United 2-0, RB Leipzig edged PSV 1-0, Villarreal beat Napoli 3-1, and Viking drew 3-3 with Bayern Munich after a late equalizer.
Matchday 2 continues Wednesday with Manchester City hosting Paris Saint-Germain, Roma facing Real Madrid, and Liverpool travelling to LASK Linz, among nine scheduled fixtures.
