The 38-year-old legend, who is a multiple-time Asian champion and a bronze-winner from the 2012 London olympics, lost 2-3 to the Colombian, giving it her all in what would now be her final Olympic bout.
Mary Kom had tears in her eyes and a wide smile on her face when the referee raised Valencia's hand at the end of the bout, exhausted after the intense clash.
The way Valencia rushed in when the first bell rang, it was quite obvious that the bout would be high voltage and it was exactly how it turned out to be.
The two were attacking each other from word go and Valencia grabbed the upper hand when she clinched the opening round 4-1.
The Manipuri veteran fought back to claim the second and the third round by 2-3 margins but the slender edge that Valencia took in the opening round tilted the final scores in her favour.
The Indian landed her right hooks to perfection in both the second and the third round.
The Indian had earlier beaten Valencia in the 2019 world championship quarterfinals and it was the Colombian's first career win over the icon.
Like Mary Kom, the 32-year-old Valencia is a trailblazer for her country.
She is the first female boxer to have represented Colombia at the Olympic Games, as well as the nation's first female boxer to win an Olympic medal.