The Brazilian forward followed his hat-trick against Celtic in the UEFA Champions League with a brace in the 2-1 league victory over Villarreal on Saturday.
That double took his tally in La Liga to six, and the 21-year-old has stepped into a pivotal role in the absence of Lionel Messi, who is missing with a hamstring injury.
Neymar is suspended for the reigning champions' next league encounter at Getafe after picking up his fifth booking of the season against Villarreal, but midfielder Iniesta stressed the importance of creating chances for the former Santos man when he is available.
Speaking to the club's official website, Iniesta said: "He can decide matches. We'll try to make sure that the player's goalscoring streak continues as long as possible."
Barcelona did not have it all their own way against Marcelino Garcia Toral's charges, as Mateo Musacchio's leveller threatened to earn a surprise draw for the visitors to Camp Nou.
However, the Catalan giants prevailed in the end and Iniesta has now challenged the side to improve performances, starting by wrapping up their Copa del Rey encounter with Cartagena, which Gerardo Martino's men lead 4-1 after the first leg.
He added: "It was very difficult but we did a lot to secure the result. We're improving, and we'll continue to improve.
"The main thing is to close out the Copa del Rey tie and try to win three points at Getafe."
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