[4] During that same season, he obtained a Spanish passport and thereby acquired Citizenship of the European Union, which enabled him to play in the first team.

[5] In the summer of 2009, Dos Santos was selected by FC Barcelona B manager Luis Enrique to form part of the second team.

[11] He made his Champions League debut for Barcelona on 24 November 2009 against Internazionale in a 2–0 win at the Camp Nou when he replaced Andrés Iniesta in the 92nd minute.

"[15] On 26 July 2011, Dos Santos started, and scored a goal, in the 2–2 draw against Sport Club Internacional in the 2011 Audi Cup.

He made his season debut on 29 August in the 5–0 home win against Villarreal, coming in as a substitute for Cesc Fàbregas in the 70th minute.

[16] On 6 December, he appeared in the starting squad and played 58 minutes against FC BATE Borisov for the 2011–12 UEFA Champions League group stage match.

[17] Despite rumours of a transfer to other Spanish clubs such as Real Betis and Málaga CF,[18] and Sevilla FC,[19] newly appointed coach Tito Vilanova officially called up Dos Santos to Barcelona's first team squad, handing him the number 12 shirt.

[20] On 6 April 2013, against RCD Mallorca, he came on as a substitute for Andrés Iniesta in the 50th minute and competed against his brother Giovani dos Santos.

[33] On 29 February 2012, Dos Santos returned to the Mexico national team for a friendly against Colombia in Miami, Florida, in which they lost 2–0.

[40] On 7 July 2019, Dos Santos scored an impressive volley in the 73rd minute that ended up being the winning goal for Mexico against the United States in the 2019 CONCACAF Gold Cup final.

[41] He is known for his work rate, technical acuity, defensive tenacity, vision and ability to create space and opportunities for teammates.