His first professional chapter came with New World, one of Madrid's most iconic club nights, where his sessions drew a growing audience and led to his first studio appearance — as a sound consultant on the club's official album, Nuclear Zone (1993). When that stage came to an end, he became one of the driving forces behind The Omen, a club that quickly transformed into a national institution and a pilgrimage destination for clubbers who travelled to Madrid from all over the country. His success pushed Oscar to evolve from resident DJ to touring artist, bringing the sound of Omen to every corner of the Iberian Peninsula and initiating what would be a lifelong relationship with airports and roads. The turning point in his international career came in 1996, when he appeared at the Sónar festival alongside Richie Hawtin, Laurent Garnier and Jeff Mills — his first appearance on a top-tier international lineup, and a moment that formally heralded to the world a new generation of Spanish techno artists. Two years later, in 1998, he released About Discipline and Education, the first mix CD of this type released in Spain. Released on the Catalan label So Dens, it fused the industrial sound of Birmingham — represented by artists such as Regis and Surgeon — with the American techno of Jeff Mills and Joey Beltram, becoming one of the best-selling electronic music albums in the country's history.