Tottenham Hotspur and Celtic were both held to draws in their Europa League openers as the British duo failed to win away to Partizan and Red Bull Salzburg respectively.
Spurs and Partizan played out a drab goalless draw in a game where both sides struggled to fashion enough clear-cut opportunities to get their Group C campaign off to a winning start.
Celtic's trip to Austria proved a little more eventful, however, as Ronny Deila's troops twice surrendered the lead in an entertaining 2-2 draw.
Alan cancelled out Wakaso Mubarak's opener for the Bhoys, before lightning struck again for the visitors after Scott Brown's strike on the hour mark was negated by Jonathan Soriano 18 minutes later.
Their Group D rivals Dinamo Zagreb stormed to the top of the pool with a convincing 5-1 victory over Romanian outfit Astra Giurgiu.
El Aribi Hillel Soudani hit a first-half hat-trick before Angelo Henriquez and Ante Coric added further goals in a quieter second half.
Inter Milan also got their Europa League campaign off to a winning start after Danilo D'Ambrosio gave them a 1-0 win away to 10-man Dnipro Dnipropetrovsk in Ukraine.
The Italian struck on 71 minutes, shortly after Ruslan Rotan received a red card as Walter Mazzarri's capitalised on their advantage.
There was no such luck for FC Zurich, however, who lost 3-2 to 10-man Apollon Limassol in Cyprus.
Limassol eased into a two-goal half-time lead courtesy of strikes from Fotis Papoulis and Marcos Gullon respectively.
However, that advantage was swiftly cancelled out in a rousing three-minute spell from Zurich in the second half, with Avi Rikan and Gilles Yipi Yapo levelling up the clash.
The Swiss club were given added impetus in their bid for a winner when Gullon was sent off for a second yellow.
It had the opposite effect, though, as a Philippe Koch own goal three minutes from the end gave Limassol the win before Yassine Chikhaoui also saw red for the visitors.
The Cypriots take an outright lead in Group A after Villarreal held Borussia Monchengladbach to a 1-1 draw in Germany.
Patrick Herrmann's 21st-minute opener was later cancelled out by Ikechukwu Uche midway through the first half.
Results in full: Apollon Limassol 3-2 FC Zurich, Borussia Monchengladbach 1-1 Villarreal, Club Brugge 0-0 Torino, Copenhagen 2-0 Hjk, Besiktas 1-1 Asteras Tripolis, Partizan 0-0 Spurs, Dinamo Zagreb 5-1 Astra Giurgiu, Salzburg 2-2 Celtic, PSV 1-0 Estoril, Panathinaikos 1-2 Dinamo Moscow, FK Karabakh 0-0 St Etienne, Dnipro 0-1 Inter Milan
