A goal in stoppage time from Aaron Ramsey gave Arsenal a 1-0 win over Marseille and the lead in Group F of the Champions League on Wednesday.
An unmarked Ramsey controlled a cross from Johan Djourou that eluded the Marseille defense to bury the ball past goalkeeper Steve Mandanda in the second minute of stoppage time.
''It is always a great achievement to come away from home and get a result,'' Ramsey said. ''I'm delighted for the team and hopefully we can continue our good form.''
Arsenal tops the group with seven points, one clear of Marseille. Olympiakos beat Borussia Dortmund 3-1 in the other group match to climb to third place with three points, two more than Dortmund.
''Everyone questioned how well we would do defensively and overall we did well,'' Arsenal manager Arsene Wenger told the UEFA website. ''The spirit is good, the attitude is right and our game is becoming stronger. There is more certainty in our display and we grow as a team from game to game.''
In a tactical first half, Arsenal's passing game was too slow to trouble the hosts, who pressed high up the pitch to steal possession.
Arsenal had the first clear chance in the 21st when a header from Netherlands striker Robin van Persie was cleared off the line by Souleymane Diawara after the Marseille defense had failed to clear a corner.
Marseille threatened in the 31st when France forward Loic Remy went past Per Mertesacker to hit a low shot that deflected off Carl Jenkinson and sailed just wide of the far post.
Arsenal's defense was again tested in the 35th with a teasing cross from winger Mathieu Valbuena. Argentine playmaker Lucho Gonzalez pounced on the cross but his close-range diversion missed the target.
''We had a difficult start,'' Wenger told Canal Plus television. ''It was a tactical deadlock with very few chances. No team managed to take the other out of position.
''There's still a lot to improve because we lost the ball a lot in the first half,'' Wenger added. ''In the second half, we managed to have more control of the game. We can especially improve in the final third. We've still got work to do but victory definitely feeds confidence.''
Arsenal dominated ball possession in the second half but struggled to create scoring chances as Marseille seemed happy to sit back and wait for counterattacking opportunities.
Czech Republic playmaker Tomas Rosicky found Theo Walcott inside the area in the 64th. The England winger moved past Nicolas N'Koulou to fire a low shot that Marseille goalkeeper Steve Mandanda stopped with his legs.
Ivory Coast forward Gervinho replaced Walcott in the 67th and slipped a through ball to Van Persie in the 90th. But Mandanda crouched to save the Dutch striker's angled effort.
Two minutes later, Ramsey finally cracked the Marseille defense.
''To lose like this in the 92nd really hurts,'' Marseille coach Didier Deschamps told Canal Plus television. ''It's unfair, it's cruel because taking a point tonight would have been a good result. We could have consolidated first place tonight with a draw.''
Arsenal was missing injured midfielder Jack Wilshere (ankle) and defenders Thomas Vermaelen (ankle), Bacary Sagna (fibula) and Kieran Gibbs (stomach muscle strain).
Marseille played without the suspended Jordan Ayew and Rod Fanni.
''In the end, we have the impression that nothing goes our way,'' Remy said. ''That's the way it is, we have to accept it. But it's hard to take.''
Arsenal and Marseille meet again on Nov. 1 while Olympiakos visits Dortmund.
