UNAM (loan)

For the Apertura 2007-2008 tournament, Sambueza was sent on-loan to Mexico side UNAM Pumas, being presented as their number 11, which was worn by legendary player Hugo Sánchez.^[3] He debuted in the Primera División against Guadalajara, with the match ending in a 1–1 draw. He played fourteen games in total, providing two assists and scoring two goals that season, against UANL Tigres, and most notably against Pachuca, which led UNAM to the playoffs, eventually losing in the final against Atlante F.C. The Clausura 2008 tournament saw Sambueza play sixteen matches, scoring two more goals and providing four assists. His loan with Pumas ended and was sent back to River Plate the following year.

Flamengo (loan)

In August 2008 Rubens moved, on loan, to Flamengo for a period of one year. He was assigned with the number 10 shirt,^[4] previously worn by club legend Zico, and vacant after Renato Augusto's transfer to Bayer Leverkusen. On 31 August he debuted for Flamengo as a substitute for Éverton in the Fla-Flu derby, when his club and Fluminense drew 2–2 for the Campeonato Brasileiro Série A.^[5]

2012–13 season

On 30 May 2012 it was confirmed that Sambueza was transferred to América, reuniting him with his former manager whilst at Estudiantes Tecos, Miguel Herrera.^[9][10][11] His first match with Las Águilas came on 28 July 2012 in a 4–2 win over Jaguares at the Estadio Azteca.^[12] He scored his first goal a week later in a 2–2 draw against Atlante.^[13] He scored the following two matches against Atlas^[14] and Querétaro^[15] in a 1–1 draw and 4–0 win, respectively. He finished his first season with América playing 16 matches, scoring four goals and having three assists. In only his first tournament at the club, Sambueza was named the club's best midfielder by the fans in a social media poll, receiving 50.75% of the votes, ahead of captain Daniel Montenegro.^[16]

Sambueza started the Clausura 2013 with an assist and scored via penalty kick in a 2–1 home win against Monterrey on 5 January.^[17] On 11 January, he scored again in the 2–0 away win against Jaguares.^[18] Sambueza played in fifteen regular season matches, scoring two goals and providing six assists. He also started in both games in the final against Cruz Azul. América won its eleventh league title, and Sambuezas' first league title in Mexico.^[19]

2013–14 season

On 31 July, Sambueza assisted in Miguel Layún's goal in a 1–1 draw against Léon in América's first match of the Apertura 2013.^[20] Three days later, Sambueza would have a Man of the match performance, assisting Raúl Jiménez and scoring off a free-kick in the 3–0 victory over Atlas.^[21] Sambueza would not score again until 21 September, when he scored a goal in América's 3–1 victory over Chiapas,^[22] and 1–0 away win against Veracruz on 28 September.^[23] On 5 October, Sambueza assisted Raúl Jiménez in scoring the first goal in the 2–0 victory in the Súper Clásico match against Guadalajara.^[24] On 26 October, Sambueza scored his first brace for América in the 3–1 win over Puebla.^[25] Sambueza received plaudits for his performance throughout the tournament, being named América's best player of the Apertura 2013 by the club fans, as he received 25% of the votes.^[26]

2016-2017 season

In the Apertura Final while America paring 1-0, he was sent off for a second yellow to make the game 10 on 10, which America ended up losing on a penalty shootout. This was his last game as an America player, as he was then transferred to Toluca.