Both former Gunners quit the North Londoners on deadline day.
Debuchy declared: "Olivier, he was a close friend. There has been a lot of talk lately. I think he chose the right option.
"It's him who feels it like that, it's him who decides. He wanted to stay in the English league. I do not worry too much about him. He's someone who always manages to score goals, and he does it very well."