Santos took the game to the Hondurans from the beginning, and they opened the scoring in the 19th minute. Marcelo Correa received a long throw, turned past his defender, and fired past the keeper from a tight angle to make it 0-1 for the visitors.
Correa soon added a second and then a third, scoring in the 31st and 37th minutes to put Santos up 0-3 at halftime.
They picked up where they left off in the second half, with Matheus Doria pouncing on a rebound to make it 0-4 in the 48th minute.
Marathón was able to reduce the deficit a minute later through Marlon Ramírez, who beat Jonathan Orozco to make it 1-4.
But Santos soon restored their four-goal cushion as Marlos Moreno scored the fifth for the Mexican team in the 60th minute, just three minutes after coming off the bench. Then, in the 67th, Julio César Furch made it 1-6 with a shot from distance.
The hosts were able to pull another goal back in the 74th minute through Yustin Arboleda, but after allowing Santos to score six away goals, they more than have their work cut out for them to stay alive in this tournament.
With the 2-6 win, Santos will advance with a win, a draw, or a loss by up to four goals in next week’s second leg, while Marathón must win by five to move on.
Marathón: Denovan Torres, Caue Fernández, Bryan Johnson, Samuel Córdova, Bryan Barrios, Mayron Flores (Marlon Ramírez Arauz 34′), Allan Banegas, Edwin Solano (Yaudel Lahera 64′), Carlos Róchez (Carlo Costly 45′), Yustin Arboleda, Carlos Discua.
Santos: Jonathan Orozco, Matheus Doria, Hugo Nervo, Jesús Angulo, José Javier Abella, Diego Valdes, José Juan Vázquez (Ulises Rivas 45′), Eduar Preciado (Marlos Moreno 56′), Brian Lozano, Julio César Furch, Marcelo Correa (Deiner Quiñones 63′)