Chasing 177 for victory, South Africa needed 30 runs from the final 30 balls with six wickets left and two set batters at the crease, but were restricted to 22 as India showed their experience and bowled with precision to close out the game.
"It is gut-wrenching. That's really what it is," Markram told reporters. "Each player has been on a different individual journey to get to this final. Ultimately, you become really tight as a group and you want good things to happen to this group because you know they're great people.
"When you get really close like that, especially the nature of how the game went, obviously adds to the emotions. It's one of those things but, we can channel it moving forward."
South Africa had lost seven semi-finals combined in 50- and 20-over World Cups over a period of 32 years before they demolished Afghanistan by nine wickets to set up the decider with India at the Kensington Oval in Barbados.
Markram hoped that this would be the first of more finals to come, in particular when South Africa host the 50-over Cricket World Cup in 2027.
"To get to our first final, it's something we can be proud of (but) still, in our eyes, not good enough. You're not satisfied with making a final," he said.
"It will take a bit of time for us to reflect back on all the good things that we've done, but obviously for the time being, it just hurts a lot.
"In hindsight, things will still feel really good about this competition. Just for the time being, it stings a bit, but it's good for it to sting. It gives you that little bit of fire in the belly for the next time that you're here."