[1] At the 2010 International Racquetball Federation (IRF) World Junior Championships, Mercado played Boys' U14 Singles for Bolivia and lost in the Round of 16 to fellow Bolivian Marcelo Vargas, 15–5, 12–15, 11–9.

[2] At the 2011 World Junior Championships in Santo Domingo, Dominican Republic, Mercado played Boys’ U16 Singles, and lost to Mexican Ramon Yanez in the quarterfinals, 15–5, 15–14.

They defeated Venezuelans Cesar Castillo and César Castro in the quarterfinals, 10–15, 15–6, 11–9, but lost to Colombians Sebastian Franco and Alejandro Herrera in the semi-finals, 15–11, 15–2, which resulted in a bronze medal.

[7] Mercado's first big IRT win came at the 2015 St. Louis Winter Rollout, when he defeated Álvaro Beltrán in the Round of 16, 5–11, 15–13, 11–5, 7–11, 11–4, on a run to his 1st semi-final appearance.

[12] In the Men's Team event, Mercado helped Colombia finish 2nd, beating Ecuador in the semi-finals, but losing to Bolivia in the final.

11–5, and reaching the semi-finals in Men's Doubles with Set Cubillos, where they lost to Costa Ricans Andrés Acuña and Felipe Camacho, 15–4, 15–3.

He played Men's Singles, beating Canadian Coby Iwaasa in the Round of 16, but losing in the quarterfinals to American David Horn, 15–12, 15–6.

[14] Mercado also played Men's Doubles at Worlds with Sebastian Franco, and they beat Guatemalans Edwin Galicia and Christian Wer, 15–12, 15–2, in the Round of 16, but lost in the quarterfinals to Americans Rocky Carson and Sudsy Monchik, losing 15–11, 15–13.

[19] Mercado also played Men's Singles in Lima, earning a bronze medal, as he reached the semi-finals with a win over American Jake Bredenbeck in the quarterfinals, 15–8, 8–15, 11–8, but in the semis, he lost to Mexican Álvaro Beltrán, 15–7, 15–5.

In Tempe, Mercado beat Alejandro Landa in the quarterfinals, 15–5, 15–9, Rocky Carson in the semi-finals, 5–15, 15–13, 11–10, and Daniel de la Rosa in the final, 6–15, 15–12, 11–0.

In Men's Singles, he lost two of his group stage matches – to Argentine Diego Garcia and Mexican Rodrigo Montoya – which meant that he didn't qualify for the medal round, although Mercado did win the consolation playoff.

[24] Finally, in Mixed Doubles with Cristina Amaya, Mercado lost in the Round of 16 to Guatemalans Edwin Galicia and Gabriela Martínez, 15–14, 13–15, 15–12, 15–8.