Roma president James Pallotta says he will pay a fine and has apologized to Mayor Virginia Raggi for jumping into a downtown fountain to celebrate the win over Barcelona.
Surrounded by a crowd of flag-waving Roma fans, Pallotta was seen performing a backward somersault in his dress shirt and pants into a fountain in the Piazza del Popolo.
Pallotta was ecstatic after Roma surprised Barcelona with a 3-0 win Tuesday to overturn a three-goal first-leg deficit in the Champions League quarterfinals.
Pallotta, a Boston executive who was part of the four-man American team that purchased Roma in 2011, is also a minority owner of the Boston Celtics.
City ordinances call for a 500 euro ($600) fine for wading into historic fountains.
After a complaint from the Codacons consumer advocacy group, the ANSA news agency reported that Pallotta called Raggi to apologize.
Roma says Pallotta was to see Raggi later Wednesday for a previously scheduled meeting.