Nicolas Nkoulou has revealed Marseille were left "truly shattered" after Aaron Ramsey's late strike earned Arsenal victory in the Stade Velodrome.
Arsenal jumped above their French opponents to take over at the top of Champions League Group F with their success last night, a 1-0 win being secured by Ramsey's stoppage-time 12-yard finish.
Marseille were content to sit on the goalless scoreline, knowing a draw would keep them in first place, so Ramsey's late effort, after he was left unmarked at the far post when a cross was swept over from the right, crushed home hopes.
Defender Nkoulou said: "I'm still feeling the shock of the defeat. The scenario is very bad. We weren't great but we weren't terrible either.
"We paid the price for letting our attention slip once."
A sliver of consolation for Marseille came with news that Borussia Dortmund had lost away to Olympiacos in the group's other game, meaning Marseille have a three-point cushion over their nearest challengers, who are now the Greek side.
"The Dortmund result still lets us believe. We are disappointed but we hope to get going again in the league from Saturday," Nkoulou said on Marseille's official website.
"We are truly shattered (by the result), we'll have to show that we are men and go looking for three points against Ajaccio.
"I am hurt but I won't dwell on it, there's a match coming up on Saturday."
The 21-year-old Cameroonian told reporters in the mixed zone after the game that the post-match frustration from Marseille's players was to be expected.
"The doors slammed, but that's normal," he said. "But we have to remember this type of defeat, it will help us in the future."
Midfielder Mathieu Valbuena also believed the late goal from Ramsey was cruel on Marseille.
Valbuena said: "The worst has happened. It's very hard to digest a defeat like that. We're all stunned, upset.
"Frankly we played a good match, there was a good spirit in the team. We didn't deserve the defeat, unlike in other games."
Goalkeeper Steve Mandanda was exposed by his defence for the decisive moment, and could not get down to Ramsey's shot which found the bottom left corner.
"It's not a happy situation. There is disappointment, anger too," Mandanda said.
"We should have been able to hang on to this result and take a point because we had done what was necessary for 91 minutes to gain a good result.
"Unfortunately we didn't hold on and for the second time this season we have let in a goal at the end which has been bad for us.
"For the goal there was a lack of concentration, communication and success. But we mustn't lament our fate.
"We are second with six points. Arsenal are ahead of us but behind us the teams are lagging."
Arsenal will have home advantage when they face Marseille again at the Emirates Stadium on November 1.
Before then, Marseille must look to emerge from their Ligue 1 doldrums, having won just one of their opening matches in the domestic competition.
Then will come the trip to London, and the chance to make amends for last night's late blow.
Mandanda said: "We would have preferred to be on seven points but now that it's happened we're not going to cry for 10 years.
"We have to get going again because we have an important match on Saturday. In the league we have to pick up some points.
"We don't have a joker left to play in Ligue 1, we have to win."