Iniesta is expected to announce his move to China in the coming days, with the 33-year-old set to call time on a stellar Barca career.
The Spain playmaker put in a typically imperious display in Barca's 5-0 annihilation of Betis' arch rivals Sevilla in Saturday's Copa del Rey final, netting the fourth goal as Ernesto Valverde's side ran riot at Wanda Metropolitano.
And Betis boss Setien, whose side sit fifth in the table, was among the mass of La Liga figures to heap praise upon Iniesta.
"Iniesta, please don't go to China, come to Betis!" Setien tweeted on his official account.
Barca's Copa del Rey triumph brought up Iniesta's 31st trophy with the Catalan club, who could claim the La Liga title next weekend should they beat Deportivo La Coruna and Atletico Madrid fail to overcome Alaves.
Iniesta, por favor, no te vayas a China, vente al Betis!!— Quique Setien (@QSetien) April 22, 2018
Iniesta's father, Jose Antonio, suggested after a Copa del Rey drubbing of Sevilla that the time has arrived for his son to depart Camp Nou.
He told Cadena SER: "He's going to make a difficult decision.
"If he chooses to leave then you have to respect it.
"I think it's a good time for him to take such a tough step and he intends to announce his decision next week."