Costas started his playing career in 1982 with Racing Club, in 1983 the club suffered a disastrous relegation from the Primera División. Costas became a key part of the team that won promotion back to the Primera in 1985. In 1988 Costas was part of the Racing Club team that won the Supercopa Sudamericana, their first major title in 21 years, they then went on to win the less prestigious Supercopa Interamaricana. Costas left Racing Club in 1992 to join Swiss team FC Locarno, after playing over 100 games for them he returned to Racing club in 1994. Costas left Racing Club in 1995 having played in a club record 298 games, scoring six goals. He joined Gimnasia de Jujuy where he played until his retirement in 1997. Costas then took charge as manager of Alianza Lima in Peru in 2003, he immediately led them to success in the Clausura 2003, and then saw his team win the Primera División Peruana final against Sporting Cristal. In 2004, he led Alianza to the Apertura 2004 title and another chance to win the final of the Primera División where they again defeated Sporting Cristal, this time 5-4 on penalties. In 2005 Costas became manager of Cerro Porteño in Paraguay, under his leadership the club won both the Apertura and Clausura in 2005 to be crowned undisputed national champions. In 2007 Costas returned to Racing Club for his second spell in charge of "La Academia". Costas has currently signed a 2-year contract to manage Olimpia of Paraguay starting at the 2008 season. In 2009 Costas returned to Alianza Lima and led them to play the final against Universitario. On 18 July 2011, he signed for Al Nassr FC from Saudi Arabia. On November 30, 2011 Due to its very poor season as coach of Al Nassr FC and all the fans angry with his work, club officials decided to end his contract. On April 11, 2012 Costas became the head coach of Ecuadorian club Barcelona. Costas had signed a one-year contract ending in June 2013. Costas won the first stage which secured Barcelona a spot to the 2012 Copa Sudamericana, 2013 Copa Libertadores and the third stage of the Ecuadorian Serie A. On December 2, 2012 Barcelona won the second stage, automatically becoming the champion of the 2012 Ecuadorian Serie A. Costas has extended his contract until December 2013. On 6 June 2019, Costas was appointed manager of Club Guaraní.
