The Frenchman remains aggrieved by February's League Cup defeat to Birmingham City, and also recalls the 'nightmare' 8-2 defeat to Manchester United at Old Trafford
The centre-back, who has featured nine times in the Premier League this season, has suggested that the club have begun to improve defensively this season however, citing Barcelona as an example of how Arsene Wenger's side should defend as a unit.
The 26-year-old told L'Equipe: "Without being mean, when you defend with four players, it is difficult. sometimes you feel alone.
"When you look at Barca, everybody defends, even Messi. There is a tendency to go forward without thinking. But it is something that has been corrected this season, especially against Marseille."
The former Lorient player also admitted that he is still aggrieved by the north London side's League Cup defeat to Birmingham City last year, and in particular the mix up between himself and goalkeeper Wojciech Szczesny that led to one of the Blues late goals.
"People retain my disagreement with Wojciech because the club is waiting for it's first trophy in six years.
"The hardest part was to get up. That's what I did. I did not expect to make 43 appearances for my first season and I had to learn faster than expected."
The Frenchman also gave his view on Arsenal's poor start to the season, including the incredible 8-2 defeat at the hands of Manchester United.
He said: "[It was] a nightmare. It took waves everywhere. It seemed that the match lasted two hours. When you pass the five goals, six, seven ... you just want the referee whistle to end the game. This was a difficult period, because everyone questioned the policy of the club, coach, players, [and also the] departures from [Samir] Nasri and [Cesc] Fabregas have destabilised the team a little."
The Frenchman played in the Gunners' 0-0 draw with Marseille in the Champions League on Tuesday, where he contributed a solid display and received his manager's praise.
"It is always gratifying from the boss. I'm happy to be part of the group."
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