Mikel Arteta worked with Sergio Aguero for just over three years during their time together at Manchester City.
Arteta was Pep Guardiola's assistant manager, while Aguero - the club's record goalscorer - played a key role in leading the team to silverware on numerous occasions.
With the news this week that his former colleague is set to leave Manchester at the end of the season, Arteta paid tribute to the Argentina international.
"First of all, I think that anybody that has been close to Sergio would say the same thing," Arteta said. "I think he's been probably the main face, or one of the main three faces that have lifted that project.
"You need some ability, you need some quality players to create moments to start to build a project like they did and Sergio was probably the biggest face on the project.
"Not only the way he plays, his charisma, his personality, the way he is. He's loved by everybody at that club. It's sad to see someone leaving like him but I think with what he's done, he'll be there for history.
"Sergio has a unique quality to see spaces that nobody else can see and to score goals in a really easy way so I'm sure that he will find the right next chapter for him."
Arteta was then asked to decide who the better foreign Premier League striker was, Sergio Aguero or Thierry Henry? But the boss remained tight-lipped on the subject.
"[Aguero] is one of the best for sure. The consistency that he's shown at this level and this league, I think it puts him right there with the best. We can discuss within that who is the best, but for me, he's one of the best."
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