The move has left a bitter taste in Stoichkov's mouth, and the 48-year-old claims that the Blaugrana's directors "do not understand" football after sanctioning the sale of their "best player".
"Because of those who do not understand football we must sell the best player we have at Barca," Stoichkov told ESPN. "The policy of Barca was always like this, they do not like great players.
"[Alexis] is the best player for his pace, his battling qualities. He fights for every ball, he plays for the team. I like his mentality. He is leaving with his head high. He is a decisive player."
Sanchez struck 19 times and bagged 10 assists in 34 Liga appearances for the Spanish giants last season.