The mixed double match that started Saturday night and finished early Sunday proved to be a surprise.
Spanish pair Fernando Verdasco and Anabel Medina Garrigues stunned men's world number one Novak Djokovic and teammate Ana Ivanovic 6-4, 7-5 to seal the overall victory, Xinhua reports.
Earlier, Serbia looked on track to win their first Hopman title when Djokovic won the men's singles clash against Verdasco 6-3, 7-5.
However, Medina Garrigues, who battled a back problem early in the tournament, levelled the tie with a 6-4, 6-7 (3-7), 6-2 win in a match lasting two hours and 38 minutes.