Axel Witsel lauded Atletico Madrid's squad depth after he was unveiled as the club's latest signing on Wednesday.

Witsel joined Atleti on a free transfer upon the expiry of his contract with Borussia Dortmund, after lucrative spells with Zenit Saint Petersburg and Tianjin Quanjian.

Despite Hector Herrera's departure, the Belgium international bolsters Atleti's midfield along with the return of Saul Niguez from his loan at Chelsea, joining Geoffrey Kondogbia and Daniel Wass as a defensive presence in the middle.

During his presentation at the Wanda Metropolitano, Witsel asserted this Atletico Madrid squad is the one with the "highest quality" over his career.

"This is a group with a lot of quality," Witsel said. "I could say many players – Koke, Joao [Felix], [Antoine] Griezmann, Yannick [Carrasco], [Matheus] Cunha.

"We have a group with a lot of quality and it is very important because there is a very good mentality, with players who always want to work hard.

"I've been through many clubs and it's true that the fact of being here and having trained with the group, I think it's the group with the highest quality of all my career. There are a lot of internationals, I'm very proud to be here and to be part of this group."

Despite his age, Witsel showed continued durability last season, only missing five games in all competitions for Dortmund last season. Their season ended poorly though, with a last-16 exit in Europa League following a group stage knockout in the Champions League, while eventually finishing eight points off Bundesliga winners Bayern Munich.

The 33-year-old also praised new boss Diego Simeone, citing him as a motivating factor behind joining Atleti, along with their ability to keep him playing at the highest level, after his expiry at Dortmund.

"It is clear, he is one of the best coaches in the world, it is one of the reasons why I am here," he said. "In recent days we have focused on the physical and I have not been able to talk much with him, but I am very proud to work with him.

"It doesn't matter how old you are, at 33 or 23 you can always learn something, and you can always learn from him.

"I was free and I chose Atletico because I wanted to continue at a high level, I know I don't have ten years left, but I want to take advantage of my last few years to play at the highest level, Atletico is at that level and that's why I'm here."