Answer:  Tennis

Hopman Cup is an international sport even related to Tennis. It is played on the hardcourt instead of the conventional lawn (grass) court. It is played in a mixed-gender team format on nation versus nation mode. 

Hopman Cup is named after prominent Australian Tennis player Hary Hopman who won 15 Davis Cup titles for his nation. This event was founded in the year 1989 and since then has been organized every year. It is an official tournament of ITF (International Tennis Federation) but the matches are not regarded as ATP (Men Tennis governing body) or WTA (Women's Tennis Association) matches. 

From 2013 it is being organized at Perth Arena Venue, Australia. The current champions are Switzerland who defeated the runner-ups Germany by 2-1 in the finals to win the title. USA has won the most titles (6 times).