"Fantasista" is the title of the latest single from Japanese Hip-hop group Dragon Ash, released in 2002.
An interesting fact about this song is that this was the official theme song for the Japanese World Cup Soccer team. The music video, coincidentially enough, features shots of soccer players doing bicycle kicks and the like in slow-motion, occasionally intercut with footage of the band performing on a soccer field in trainers.
As for how the song sounds, I would describe it as a mixture of rap rock, hip hop, woah punk, and techno, with elements from each genre blended to create a high-energy anthem.
As a side note, even with the help of this song, Japan did not win the World Cup; that honor went to Korea instead. :(