Dani Carvajal described Iran's tactics as "disloyal" even though Spain recorded their first World Cup win.
Iran had a goal disallowed following a VAR review, while Mehdi Taremi was among those to miss chances for Carlos Queiroz's side.
Real Madrid right-back Carvajal, though, felt Iran's defensive tactics were over-the-top, while hitting out at what he perceived to be play-acting.
"The team sits back and that is a tactical strategy that is part of the game," Carvajal said.