Italian giants Lazio were fortunate to escape with a 2-2 draw against Romanian side Vaslui in their opening Europa League Group D clash at the Stadio Olimpico.
Edy Reja's men played the last half-hour with 10 men following the dismissal of defender Luciano Zauri and had to rely on Giuseppe Sculli's 71st-minute strike to avoid deeper embarrassment.
Djibril Cisse's 35th-minute penalty had given the hosts the lead but a brace from Brazilian Wesley early in the second half gave Vaslui the scent of glory before Sculli came to the rescue.
In the same pool, Sporting Lisbon made a more impressive start with a 2-0 win over FC Zurich in Switzerland. Emiliano Insua opened the scoring after four minutes and Ricky van Wolfswinkel added a second.
Former European champions PSV Eindhoven relied on a piece of magic from Dries Mertens to nudge past visitors Legia Warsaw 1-0 in Group C. The Belgium winger lashed home the only goal of the game after 21 minutes.
Stoke were denied a winning start to their Europa League Group E campaign by Dynamo Kiev's late equaliser on a night with no wins for British or Irish clubs.
The Ukrainian hosts dominated the first 45 minutes and should have gone ahead midway through when Andriy Yarmolenko blazed wide with the goal at his mercy.
Having weathered the storm, the Potters took the lead 10 minutes into the second half when Cameron Jerome finished from Ryan Shotton's cross, but after Oleksandr Aliev had hit the bar for Dynamo, Ognjen Vukojevic made it 1-1 in stoppage time.
Ovidiu Herea's second-half strike was enough to give Rapid Bucharest a winning start to their Group C campaign at Hapoel Tel-Aviv.
Besiktas strolled to the top of Group E with a 5-1 triumph over Maccabi Tel-Aviv in a highly-charged atmosphere in Istanbul.
An inexperienced Tottenham side came through a nail-biting finish to leave the cauldron of the Toumba Stadium with a hard-fought goalless draw in the Group A clash against PAOK Salonika.
Carlo Cudicini was called upon to make three fine saves late on and Vladimir Ivic rattled the Italian's bar in stoppage time amid a white-hot atmosphere in Greece.
Lino missed a re-taken first-half penalty for the hosts while debutant Yago Falque twice went close for Tottenham and Harry Kane might have been awarded an earlier spot-kick after being brought down in the box.
It was a tough night in Group A's other game for Shamrock Rovers as the Irish side lost 3-0 to Rubin Kazan.
Obafemi Martins had opened the scoring at Tallaght Stadium after just three minutes and Christian Noboa made it 2-0 five minutes after the break.
Gokdeniz Karadeniz was the star of the show for the Russians and he capped a fine individual display with a sweetly-struck third on the hour.
Rubin striker Nelson Valdez had earlier seen a first-half penalty saved by Ryan Thompson, and Sergei Ryzhikov matched his feat to keep out Stephen O'Donnell's 64th-minute spot-kick.
Paris St Germain got their Group F campaign off to a strong start with a 3-1 win over Salzburg.
Nene opened the scoring from the penalty spot in the 35th minute and Mathieu Bodmer doubled their advantage just before the interval.
Jeremy Menez made the points absolutely safe by bagging the third goal midway through the second half, rendering Ibrahim Sekagya's 87th-minute header little more than consolation.
In the same group, Athletic Bilbao grabbed a 2-1 victory at Slovan Bratislava.
Rising star Iker Muniain struck the winning goal as Bilbao secured a win that should help ease the pressure on new coach Marcelo Bielsa.
Teenager Muniain netted what would prove to be the deciding goal in the 40th minute, not long after Slovan defender Karim Guede had cancelled out Markel Susaeta's opener in the clash at the Pasienky stadium.
Hannover and Standard Liege played out a painfully uninspiring goalless draw in their Group B opener in Germany, while Morten Nordstrand's second-half penalty settled a low-key encounter in FC Copenhagen's favour as they edged Ukrainian side Vorskla 1-0 in Denmark.
Celtic's dismal European away record continued with a 2-0 defeat to Atletico Madrid in their Group I opener in Spain.
The Hoops were still warming to their task when Colombian striker Radamel Falcao met a Diego corner in the third minute to head past Hoops goalkeeper Fraser Forster.
Diego added the second in the 67th minute to leave the Parkhead men with one away win in Europe in 31 games ahead of Sunday's Old Firm clash at Ibrox.
In the same group, a late winner by Pablo Armero helped Udinese get over their Champions League elimination by Arsenal with a 2-1 win over Stade Rennes.
Youssouf Hadji earlier gave the visitors a deserved lead in the 18th minute and Udinese were fortunate not to fall further behind before Antonio Di Natale grabbed a 39th-minute leveller.
Mark Schwarzer's own goal meant Fulham and FC Twente drew 1-1 in their Group K clash at Craven Cottage.
The west Londoners dominated the encounter for the most part and broke the deadlock after Andrew Johnson flicked home a neat effort.
However, the Dutch outfit levelled before the break as Luuk de Jong's header bounced off a post and in off Schwarzer.
Birmingham's dream of making a flying start to their Group H campaign was brought crashing back down to earth as they lost 3-1 to Braga.
Last season's beaten Europa League finalists had too much class in front of goal to leave Chris Hughton's side with an uphill task already if they are to qualify for the knockout phase.
Two goals from Helder Barbosa, early in the game and again late on, sunk the Blues after Marlon King had offered the hosts a glimmer of hope following a controversial effort from Lima that had given the visitors a 2-0 lead.
Matias Suarez hit a hat-trick as Anderlecht thrashed AEK Athens 4-1 in their Group L opener in Belgium, while Schalke could not break through a resolute Steaua Bucharest defence and had to settle for a goalless draw in Group J.
In Group G, goals from Josmer Altidore, Rasmus Elm, Adam Maher and Brett Holman earned AZ Alkmaar a crushing 4-1 win over Malmo, whose consolation came from a 72nd-minute Daniel Larsson penalty.
Also in Group G, Ukrainians Metalist Kharkv hit back from a goal behind to win 2-1 away to Austria Vienna. Second-half goals from Papa Gueye and Cleiton Xavier cancelled out Tomas Jun's early effort.
In Group H Club Brugge beat Maribor 2-0 with early goals from Vadis Odjidja-Ofoe and Nabil Dirar, while Maccabi Haifa shrugged off a poor domestic campaign to edge AEK Larnaca via Mohammad Ghadir's only goal in Group J.
Danish side Odense swept to a surprise 3-1 win over Wisla Krakow in Poland and in Group L Lokomotiv Moscow came from behind to win 2-1 at Sturm Graz with goals from Victor Obinna and Dimtri Sychev.
Europa League Results