Alexis Sanchez's departure from Barcelona does not mean he is a bad player, Dani Alves has stressed.
The Arsenal forward spent three seasons at Camp Nou between 2011 and 2014, scoring 38 goals in 88 La Liga games for the club before moving to England.
Alves feels the Chile international has proven he is a "beast of a player" but insisted that alone is no guarantee for success at Camp Nou.
The two players will do battle when Barcelona host Arsenal in the second leg of their Champions League last-16 tie on Wednesday.
"Alexis didn't fail at Barcelona but it's hard to play here because you have to understand the playing idea," the defender, 32, told the Daily Mail of his former team-mate.
"He's a great player and I always knew that he would be a success when he left, especially if he went somewhere he would be the protagonist. He's the kind of player who needs that.
"In the end, you are going to have the protagonism anyway but you have to understand that, at Barcelona, it's not enough just to be a great player.
"You need to have a great understanding of the way Barcelona play and, if you do, then you will have a long career here.
"Those that come and go, that doesn't mean they are bad players.
"They go somewhere else and they enjoy it because they are beasts, but at Barcelona it's not enough just to be a beast of a player."
Sanchez, 27, has scored 11 goals in 31 appearances for the Gunners in 2015-16.
