Wenger had claimed the quartet of Marseille, Rafael Benitez's Napoli and last year's runners-up Borussia Dortmund made Group F the hardest of the competition. The Frenchman also conceded that unless their injury situation improved - currently eight first-team squad members are out - then they would struggle to make it out of the group for the first time since the 1999/2000 season.
Wenger will therefore have been all the more relieved to see his side pick up yet another win on the road on the French south coast. Theo Walcott and Aaron Ramsey's second-half strikes proved the difference at the half-finished Stade Velodrome, where the hosts dominated for large periods of the match.
"It was important for us not to give the first goal away and I thought Marseille had an excellent first half," Wenger said. "We were a bit timid overall and in the second half they dropped and we took advantage of our good moments in the game. It was a victory linked with patience and experience, even if we were not flamboyant. But we start with three points and that is good. I knew that it would be a difficult game. Marseille is a good side, they can beat anybody here."
Marseille, back in the competition after a year's absence, edged the first half, with Andre Ayew and Andre-Pierre Gignac coming closest. Rod Fanni was inches away from opening the scoring moments into the second half, before Kieran Gibbs saved Per Mertesacker's blushes by clearing his miskick off the line as Gignac waited to nod into an empty net.
That proved decisive as another defensive mistake at the other end put Arsenal in the driving seat. Jeremy Morel misread a Gibbs cross, allowing Walcott time to rifle into the roof of the net and quieten those who had criticised his finishing during Saturday's 3-1 win at Sunderland.
The hosts pressed for a leveller but Ramsey's low strike seven minutes from time put the game out of reach for the hosts, who pulled one back through substitute Jordan Ayew's stoppage-time penalty. "It was vital to get three points and get off to a good start here," Ramsey said. "It was a difficult night, the pitch was sticky and slow, we didn't quite get the rhythm in our passing going. I think we deserved it."
Ramsey now has six goals this season and he added: "I'm happy with the way I'm playing. I'm playing with confidence and I'm getting into positions and putting them away."