The France fullback believes communication is key when he plays at the heart of defence.
"It's a good job," he told Arsenal Player when asked about playing at centre half. "It's different from right back. You're racing a bit more.
"You have to be even more focused because at the back you're not allowed to [make] any mistakes. As long as you communicate with your partner, it makes the job a bit easier.
"We wanted to qualify and now we've done it. We played OK tonight. We didn't play our best football but at least we won. We stayed focused until the end and we managed to score goals. It was most important to win to keep our confidence high.
"It's a must for Arsenal Football Club. It's a must for us and the fans to be part of the Champions League. We knew it was a great game to play and tonight we can be happy because we did the job properly and we qualified."
For the big stories and the banter follow us on Twitter: @tribalfootball