Pique headed the equaliser in a 1-1 draw against Barca's neighbours in LaLiga on Sunday, celebrating by putting his finger to his lips and 'shushing' the home fans at RCDE Stadium.
The centre-back made headlines after a recent Copa del Rey success against Espanyol by referring to the club multiple times as "Espanyol de Cornella" – a suburb of the Barcelona metropolitan area - rather than Espanyol de Barcelona.
Espanyol subsequently reported Pique to the Spanish Football Federation and he was booed throughout Sunday's match, making his equaliser for Barcelona an even sweeter moment for the Spain international.
And Iniesta suggested Pique's celebration, which contributed to ugly scenes in the closing stages of a game played in sodden conditions, was par for the course in a passionate encounter.
"These things happen in derby matches," Iniesta said. "I don't know the exact gesture that Pique made. I hope everything is very calm.
"We had a point and we were still pushing up. We couldn't get all three points. The conditions weren't as bad for them as they were for us.
"I wouldn't say it was difficult for us to adapt to the pitch. I think we played a great game. We put in a big effort and were able to rescue ourselves and avoid a 1-0 defeat."
While Iniesta was happy to write off Pique's antagonistic celebration, Espanyol coach Quique Sanchez Flores suggested the feud between his club and the player will continue as a result.
"Pique cannot silence the fans, especially not ones like ours," Flores told reporters.
"The fans are well above this kind of things. They will respond in the coming days.
"The season doesn't end or start with Barcelona, we are optimistic and positive about the coming months. There are details in these matches which define the outcome and they don't depend on us.
"Sometimes football brings these kinds of situations, I hope we can continue to compete without making mistakes."