The Spain star has backed his Brazilian teammate to be a success at the Catalan side during his first season and regards Cesc Fabregas as a crucial part of the squad.
The forward completed a switch from Santos in a deal worth $75 million during the summer transfer window but, following his arrival in Spain, critics have questioned his ability to perform at the top level in Europe.
However, his experienced teammate is certain the Brazil star, who Barca revealed suffers from anemia, will be an instant success at the club.
"I don't think he will need much time to adjust," Iniesta told reporters in Bangkok, where Barca has arrived following its Peace Tour. "When you're the best and you get to our team, you adapt quickly. Despite coming from another league, he will contribute much.
"His signing only brings positive things to us."
Iniesta also commented on Cesc Fabregas and his standing in the team, as the midfielder looks to set to stay at Camp Nou with Manchester United having given up on signing the Spaniard, according to Barca director Andoni Zubizarreta.
"For me, he [Fabregas] is undisputed in this club," Iniesta said. "My teammates are always the best and the important thing is that competition makes us all better, because ultimately the team are winning the titles, not the individuals.
"He is a key player for us, he always performed at the highest level and will continue to do so."