River Plate's Enzo Perez failed from 12 yards to send Al Ain through to the Club World Cup final after the last-four clash had ended 2-2.
Al Ain caused a major upset at the Club World Cup on Tuesday as they dumped Copa Libertadores winners River Plate out on penalties in the semi-finals.
Nine days after they were crowned South American champions for a fourth time, River were unable to book a second Club World Cup final appearance as Enzo Perez missed the decisive spot kick after the match had finished 2-2 after 120 minutes.
Rafael Santos Borre had given River hope with a first-half double to cancel out Marcus Berg's scrappy opener, the Colombian's brace taking his tally to four goals in his last two outings.