Óscar de Marcos Arana is a Spanish footballer who plays for Athletic Bilbao in La Liga, mainly as a midfielder. Oscar made his professional debuts for hometown's Deportivo Alavés, first appearing in a second division home fixture against CD Tenerife, on 21 December 2008. In July 2009, Oscar signed with Athletic Bilbao on a four year deal for about €350.000. He made his club debut on 6 August in a 2–1 win at BSC Young Boys for the UEFA Europa League; ten days later he opened the score against FC Barcelona for the season's domestic supercup as the Basque eventually lost 1–2 at home and 1–5 in total. Only in May 2010 did he start playing with the B's, helping them narrowly avoid relegation from division three. De Marcos netted on both legs of the 2011–12 Europa League round-of-16 against Manchester United, as Athletic won both games and went through 5–3 on aggregate.