Manchester City maintained their perfect start in Group C after thrashing Marseille 3-0 at Stade Velodrome.
Off-season signing Ferran Torres got the only goal of the first stanza for City before IIkay Gundogan and Raheem Sterling wrapped up the three points in the second half.
FC Porto secured their victory in Group C after beating Olympiacos Piraeus 2-0 at Estadio do Dragao.
Fabio Viera gave the Portuguese an early lead and Sergio Oliveira sealed the three points with the second goal in the last five minutes.
Atalanta came back from two goals down to rescue a 2-2 draw against Ajax Amsterdam in a Group D clash at ATleti Azzurri d'Italia.
Dusan Tadic and Lassina Traore gave the Dutch giants a two-goal cushion heading to the halftime break.
However, Duvan Zapata netted twice in a space of six minutes before the hour-mark to keep Atalanta's unbeaten record.
Atletico Madrid won their first match of the campaign after edging RB Salzburg in a five-goal thriller at Estadio Wanda Metropolitano.
Marcos Llorente got the opener for the hosts just before the half-hour mark but Dominik Szoboszlai and Mergim Berisha struck twice late in the first stanza to give the visitors a 2-1 lead.
Joao Felix levelled matters for Atletico eight minutes from the break before he went on to snatch the winner in the last five minutes.
