Pablo Armero, Teofilo Gutierrez and James Rodriguez were on target to ensure Greece's FIFA World Cup campaign got off to a miserable start in Belo Horizonte.
The defeat dents Greece's hopes of making it out of a World Cup group for the first time, but Santos insists all is not lost.
"It's not a tragedy," he added. "It is a setback that complicates the situation.
"I will talk with my players, we will look at our mistakes to correct the situation and in the next two matches we will present ourselves better."
Santos was under no illusions as to why his team slipped to such a convincing defeat.
"Congratulations to Colombia, they were the better team and fairly won 3-0," Santos said.
"We had opportunities, we had effort but we paid for our mistakes."
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