
Former Champions League participants Panathinaikos had the ideal start at home against their Scottish visitors as Austrian international Andreas Ivanschitz's free-kick to the front post was met by Ioannis Goumas, whose header hit the back of the net.
It was Ivanschitz who also created Panathinaikos' second in the 73rd minute as his defence-splitting pass found Dimitrios Papadopoulos, whose low shot gave goalkeeper Jamie Langfield no chance.
Another Ivanschitz free-kick four minutes later found Dimitrios Salpingidis being able to pounce onto a lose ball that Langfield had managed to clear at the first attempt. Salpingidis made no mistake from close range to give the home side their 3-0 win.
The other game in the group saw Lokomotiv Moscow and Atletico Madrid share the spoils in an exciting 3-3 draw.
Atletico Madrid took the lead through Aguero, only for Diniyar Bilyaletdinov to find a equalizer for the home side. Diego Forlan, however, put the La Liga side ahead again before the break.
Nigerian Peter Odemwingie thought he had given the home side the three points with two goals in the second half, but Aguero's second on the night five minutes from the break was enough to give Atletico a point from their first European match since 1999.
In Group D Bundesliga club SV Hamburg spoiled Brann Bergen's celebrations with a 1-0 victory in Norway.
The home side, that won the championship for the first time in 44 years on the weekend, managed to withstand Hamburg's pressure for an hour, but could do nothing against Vincent Kompany's shot from all of 20 metres in the 62nd minute. The Belgian international was somewhat fortuitous as his effort as the ball hit the post and rolled over the line.
There was also a 1-0 success for fellow Bundesliga club Bayer Leverkusen, who managed to beat French team Toulouse in a Group E game played in Germany.
Toulouse will count themselves unlucky to have returned to France without at least a point after creating several chances, but failing to score from them. They will also feel cheated by Stefan Kiessling's 35th minute goal, that the striker scored after seemingly playing the ball with his arm.
Also in Group E Zurich came from behind to win 2-1 at Slavia Prague. Miroslav Slepicka gave the home side the lead in the 24th minute, but Oumar Konde equalized equalized before the break.
Alexandre Alphonse scored a second for Zurich on the hour and the Swiss side then had to wait some anxious moments as they were reduced to ten men after Eric Hassli was sent off with ten minutes remaining, but Slavia could not make their numerical advantage count.
There was partial success for another Greek club as Panionios managed a good 1-1 away draw in Sweden against Helsingborg in their Group H match.
Swedish veteran Henrik Larsson, who played in the UEFA Cup final in 2003 with Celtic, spared his side's blushes with a 83rd minute equalizer after Fanourios Goundoulakis gave Panionios a first-half injury time equalizer.
Bordeaux are the first group leaders in Group H after scoring twice in the second half to defeat Galatasaray 2-1. Shabani Nonda scored from the spot in the 22nd minute to give the Turkish visitors a first-half lead, but Fernando Cavenaghi and Marouane Chamakh turned things around for Bordeaux in the second half.
A ten-man AZ Alkmaar, who played the entire second half with one man less, drew 1-1 against Zenit St. Petersburg in their Group A game.
Brazilian forward Ari gave the visitors the lead midway through the first half with a well-taken shot from just inside the penalty area. He turned from hero to villain shortly afterwards though, as he was red-carded.
Zenit equalized at just the right time as Anatoliy Tymoschuk scored from the spot after Kew Jaliens brought down Andrei Arshavin in the area.
Even though they enjoyed more of the possession in the second half, the home side could not find the match winner against their 10- man opponents.