He first progressed beyond the pre-qualifying rounds of any event at the 1991 Grand Prix, where he won six matches - including a 5–0 whitewash over the fading Alex Higgins - before losing 2–5 to Ken Doherty in the last 96.

The 1996/1997 season heralded some success for Rosa, as he reached the main stages of a ranking event for the first and only time in his career, at the 1997 International Open.

During the following season, having dropped off the main tour in 1997, Rosa reached the semi-final of one tour qualifying event, losing 3–5 to Antony Bolsover, and the sixth qualifying round at the 1998 World Championship, where he beat Rory McLeod 10–8, Darryn Walker 10–9, Stuart Bingham 10–7 and Marco Fu 10–8 to face David Gray.

Having again fallen out of the professional ranks by 2000, Rosa won the first event of that year's Challenge Tour, beating Surinder Gill 6–4 in the final.

The next season was poor, however, with only three victories; two of these came in the 2001 Benson & Hedges Championship, over Mark Ganderton and Joe Jogia, before he lost 2–5 to Shaun Murphy at the last-32 stage.