Mercado earned three silver medals at the
2018 South American Games in
Cochabamba,
Bolivia, one each in Men's Singles, Men's Doubles and the Men's Team event. In singles, he defeated
Carlos Keller of Bolivia in the semi-finals, 15–8, 15–14, but then lost to the other Bolivian
Conrrado Moscoso, 15–10, 11–15, 11–6, in the final. In doubles, Mercado and
Sebastian Franco finished second in a five team round robin with their only loss to Moscoso and Roland Keller, 15–11, 15–7. In the Men's Team event, Mercado helped Colombia finish 2nd, beating Ecuador in the semi-finals, but losing to Bolivia in the final. Mercado played for Colombia at the
2018 Central American and Caribbean Games in
Barranquilla,
Colombia, where he got the finals in Men's Singles, losing to Mexican
Daniel de la Rosa, 9–15, 15–2. 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. In the Men's Team event, Colombia lost in the quarterfinals to Cuba, as Mercado won his match, but he and Cubillos lost in doubles and the final singles match was lost also. So, Mercado came away from Barranquilla with two medals: silver in Men's Singles and bronze in Men's Doubles. In 2018, Mercado played at the IRF World Championships for Colombia. 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. 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. Mercado was in another semi-final in the 2018–19 IRT season, when he reached the semis of the 2019 Bolivian Open. He defeated Andree Parrilla in the quarterfinals, 15–7, 15–11, but lost to
Rocky Carson in the semis, 15–8, 6–15, 11–6. However, Mercado only had one other quarterfinal appearance that season, so he was ranked 10th at season's end. In doubles, he and Andrés Gómez lost to Roland Keller and
Conrrado Moscoso, 15–3, 15–5, in the quarterfinals. At the
2019 Pan American Games in
Lima,
Peru, Mercado was part of the silver medal Colombian Men's Team in the
Men's Team event, which was Colombia's first racquetball silver medal at the
Pan Am Games. They beat the Canada in the quarterfinals, 2–0, then defeated Mexico in the semi-finals, 2–1, before falling to Bolivia in three matches in the final, 2–1. In the final, Mercado defeated
Carlos Keller but they lost in doubles and team-mate
Sebastian Franco lost to
Conrrado Moscoso. 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 the 2019–20 season, Mercado reached his 2nd final at the 22nd Annual Lou Bradley Memorial Pro-Am in Sun Prairie, Wisconsin. He reached the final with a win over
Alejandro Landa, 15–14, 15–11, in the semi-finals, but
Kane Waselenchuk defeated Mercado in the final, 15–2, 15–3. Yet, Mercado only made it past the Round of 16 three times that season with the other two being quarterfinal losses, and that led to a 13th ranking at season's end, which was the first time he was ranked outside the top 10 while playing the IRT full time. Mercado is the third South American and second Bolivian born player (after
Conrrado Moscoso) to win an IRT event. At the
2022 Pan American Racquetball Championships in
Santa Cruz de la Sierra,
Bolivia, Mercado played three divisions: Men's Singles and Men's Doubles as well as Mixed Doubles, which was offered for the first time in 2022. However, Mercado didn't reach the podium in Santa Cruz. 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. In Men's Doubles, Mercado and Set Cubillos lost in the quarterfinals to American brothers Jake Bredenbeck and Sam Bredenbeck, 15–14, 15–9, 15–8. 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.
Career record This table lists Mercado's results across annual events. Note: W = winner, F = finalist, SF = semi-finalist, QF = quarterfinalist, 16 = Round of 16. P = pandemic cancelled event. ==Personal life==