Antoine Griezmann will fit Barcelona like a ring on a finger, according to his former coach at Real Sociedad.

Griezmann finally completed his long-awaited move from Atletico Madrid to Camp Nou on Friday having seemed set to join Barca last year before opting to stay put.

Barca triggered the €120million release clause in his contract, although Atletico are demanding a further €80m as one of modern football's longest transfer sagas rumbles on.

Griezmann will line up for Barca next term, though, bolstering the attack of the LaLiga champions, who have also been linked with a deal for Paris Saint-Germain superstar Neymar.

It is unclear exactly how Griezmann slots into the plans of Barca boss Ernesto Valverde, who regularly paired Lionel Messi and Luis Suarez as a front two during 2018-19.

But Martin Lasarte, who coached Griezmann when the France forward was breaking through at Real Sociedad, feels the adjustment to Barca will be smooth for the striker.

"His signing for Barcelona - it would have happened last year, so it's something everybody knew," Lasarte told Omnisport. "Barcelona supporters were angry but I think staying at Atletico was the right decision for him.

"Now I think it's the right time [to move] because after Barcelona failed to win all the trophies last season - and in a bad way - so I think Griezmann could fit easily and help them to come back, because he is a happy guy and a very positive one.

"I think Griezmann will fit like a ring on a finger after Barcelona's situation last season."

Lasarte is perhaps uniquely placed to comment on Griezmann's rise having played a key role in his development.

"Well, it is difficult to be original when you define someone everybody knows," the coach said. "I trained a very young player that obviously has grown up.

"He made a giant step to become one of the best strikers in the world. Anyway, he still keeps some of the things he had when he was a child. He knows how to read the game. All of us are impressed with how he passes the ball, how he dribbles, or how he shoots the ball.

"He is a very smart guy, he knows how to take decisions on the pitch. He knows when he need to speed up, when to stop, or pass the ball short or long, or when to dribble."

Griezmann will be formally presented as a Barcelona player at a news conference on Sunday.