On 13 October 2014, de Marcos agreed to a new three-year extension until 30 June 2019, with a buyout clause being set at €40 million. He also featured in all ten matches in both the UEFA Champions League and Europa League, but did not take part in the 2015 Spanish Cup final due to suspension (once again the result was a defeat to Barcelona, and his inexperienced replacement Unai Bustinza struggled to cope with the skill of Neymar); he did play the full 180 minutes of the 2015 Supercup, in which his club finally overcame the same opponent.