(CNN) -- English Premier League Arsenal have got one foot in the draw for the Champions League group stage after a comfortable 2-0 victory at Celtic in the first leg of the 'battle of Britain' qualifier.
William Gallas celebrates scoring Arsenal's opening goal in their 2-0 Champions League victory at Celtic.
Two slightly fortunate goals, through defender William Gallas and an own goal from Celtic captain Gary Caldwell, gave the Gunners a commanding advantage to take into the second leg at The Emirates Stadium.
Arsenal went into the match on the back of their stunning 6-1 Premier League win at Everton, a match in which Gallas was also on target, and the French defender made it two goals in two games with a huge slice of luck.
Roared on by their passionate home supporters, Celtic held their own for much of a frantic first half but in the 43rd minute Cesc Fabregas' drive from 30 yards out took a wicked deflection off Gallas' back to send the ball past goalkeeper Artur Boruc.
Then, Arsenal all but booked their passage into the next round in the 71st minute when Caldwell diverted the ball past Boruc in his attempt to cut out a Gael Clichy left-wing cross.
Arsenal manager Arsene Wenger told Sky Sports: "It was a fierce fight and Celtic gave absolutely everything.
"Overall I think we controlled the game but were lucky with the two goals we scored. Their energy tonight was sensational.
"Defensively they did very well and they never gave up. We are in front after 90 minutes so let us make sure we are in front after 180."
There were four other Champions League matches on Tuesday, with the most exciting encounter coming in Portugal as Italian Serie A side Fiorentina claimed a 2-2 draw at Sporting Lisbon after recovering from two goals behind.
The hosts dominated for large periods and scored in quick succession through Simon Vukcevic -- who was then sent off for a second bookable offence when he took his shirt off to celebrate his goal -- and Miguel Veloso at the start of the second half.
But goals at the start and end of the match from Juan Manuel Vargas and Alberto Gilardino tipped the scales in the Italians' favor.
Bundesliga side Stuttgart can also be confident about taking their place in the group stage after defeating Timisoara 2-0 in Romania.
Youngster Timo Gebhardt gave Stuttgart the lead from the penalty spot in the 28th minute before a fine individual goal from Alexander Hleb two minutes later sealed the win.
Greek side Olympiakos also have one foot in the group stage after beating FC Sheriff 2-0 in Moldova.
Brazilian Dudu fired the visitors in front immediately after the interval and substitute Konstantinos Mitroglou, who had only been on the pitch a matter of seconds, doubled their lead nine minutes before the end.
FC Copenhagen take a slender advantage into the second leg after they secured a 1-0 home win over APOEL Nicosia.
Zdenek Pospech scored the only goal of the game in the 54th minute. Altin Haxhi was sent off in stoppage time to complete a miserable night for the Cypriot visitors.