May 2012, a permanent deal was arranged, but for €11 million. Guarín scored his first official goal for the Nerazzurri on 30 August, in a 2–2 home draw against FC Vaslui in the Europa League (4–2 on aggregate). In the group stage of the same competition, he provided all three assists in a 3–1 defeat of Neftchi Baku PFC. Again in the Europa League, on 21 February 2013, Guarín scored twice in a 3–0 away win over CFR Cluj (5–0 on aggregate) to help Inter make it through to the last 16. In the January 2014 transfer window, he was supposed to move to Juventus F.C. in exchange for Mirko Vučinić, but the deal ultimately fell through after the clubs could not reach an agreement. He declared he would not return if he was not allowed to leave, but eventually he reconsidered; it was later reported that he simply wanted to clarify his future with the club, stating that he never asked to leave and that he was confused as to why the situation was created. On 25 March 2014, Guarín agreed to extend his contract until 2017. On 14 September, as a second-half replacement, he scored in a 7–0 home win against U.S. Sassuolo Calcio. At the start of the 2014–15 season, he began being used by manager Walter Mazzarri as a second striker. On 7 December 2014, in his 100th appearance for Inter, Guarín assisted Mauro Icardi in the 44th minute of an eventual 1–2 home defeat to Udinese Calcio. On 16 February of the following year, he scored twice after winning a first-minute penalty kick in a 4–1 victory at Atalanta BC, helping his team to secure the first away win in the league since December 2014. Later career On 26 January 2016, Guarín joined Shanghai Greenland Shenhua F.C. in the Chinese Super League for a reported €11 million fee plus bonuses. On 26 September 2019, the 33-year-old free agent moved to the Campeonato Brasileiro Série A with CR Vasco da Gama. Guarín agreed to a one-year deal at Millonarios F.C. on 31 December 2020, again on a free transfer. International career On 24 May 2006, Guarín made his international debut for Colombia, in a pre-World Cup friendly against Ecuador. He represented the nation at the 2005 CONCACAF Gold Cup and the 2011 Copa América. Guarín was selected by José Pekerman for his 2014 World Cup squad.