Liverpool kicked their Europa League campaign off with a thrilling 5-3 win over Young Boys in Switzerland on Thursday.
Juhani Ojala's bizarre own goal gave the Reds the lead in the fourth minute and, though Young Boys fought back when a defensive lapse allowed Raphael Nuzzolo to equalise, Andre Wisdom's header soon restored his side's lead.
The hosts pushed on in the second half, allowing Ojama to make amends for his earlier mishap with a goal of his own before Gonzalo Zarate turned the game on its head.
However, Sebastian Coates equalised from a corner before substitute Jonjo Shelvey scored twice to seal three points for the Merseysiders.
Atletico Madrid had the best possible start to the defence of their crown after comfortably disposing of Hapoel Tel Aviv 3-0.
First-half goals by Christian Rodriguez after 37 minutes and Diego Costa three minutes later gave the Spanish side the upper hand. Raul Garcia made sure of the three points in the 63rd minute.
Tottenham and Newcastle United were held to 0-0 stalemates by Lazio and Maritimo respectively while Chilean Eduardo Vargas scored a hat-trick as Serie A outfit Napoli trounced AIK 4-0.
Yuto Nagatomo scored an injury time equaliser for Inter Milan as they drew 2-2 with Rubin Kazan while Joey Barton made his Marseille debut – his suspension does not apply to European fixtures – in another 2-2 draw against Fenerbahce of Turkey.
In other matches, Lyon beat Sparta Prague 2-1, Viktoria Plzen came from behind to beat Academica 3-1, Bordeaux eased past Club Brugge 4-0, FC Copenhagen edged Molde 2-1 and Athletic Bilbao drew 1-1 with Ironi Kiryat Shmona.
Antonio Di Natale's injury time effort saw Udinese snatch a point in a 1-1 draw with Anzhi Makhachkala, Dnipro Dnipropetrovsk beat PSV 2-0, Levante edged Helsingborg 1-0 while Genk and Maribor notched 3-0 triumphs over Videoton and Panathinaikos.
FC Twente and Hannover played out a 2-2 draw, as did Stuttgart and Steaua Bucharest, while Rosenborg won 2-1 at Rapid Vienna.
Matches involving AEL and Borussia Moenchengladbach, Bayer Leverkusen and Metalist, Sporting Lisbon and Basel and Partizan Belgrade and Neftci all ended goalless.