Balcells 1996 professional tennis player and reached at the first Grand Slam tournament of his career the quarterfinals. The following year, he was in the doubles final of the Challenger tournament in Bratislava. In 1998, he played for the first time on the ATP World Tour and reached the quarterfinals of the tournament in Bogota. In addition to two double Challengertiteln he reached the semifinals of the tournament in Gstaad on the side of Alberto Berasategui.
In 2000 he reached the semi-finals as a qualifier of Auckland, un which he defeated Michael Chang. In the same year he was able to win his only individual title on the ATP World Tour; at the tournament in Bucharest, he won against the Markus Hantschk. Its highest listing in the tennis world ranking he reached in 2001 with position 57 in singles and position 65 in doubles.
His best individual result at Grand Slam tournaments was reaching the second round of the French Open in 2000 and 2001. In doubles he stood in 2001 in the quarterfinals of Wimbledon.
Balcells played between 1999 and 2002 three singles and nine doubles matches for the Spanish Davis Cup team, and won with this the Davis Cup title in 2000. He stepped out of the first round to the finals on the side of Alex Corretja in to double. You could win all their games double up on the quarter-final match against Yevgeny Kafelnikov and Marat Safin. He also won the 5-0 semi-final victory against the United States in the last, meaningless match against Jan-Michael Gambill.