It was not a straightforward evening for the South Americans. Congo DR goalkeeper Lionel Mpasi was extraordinary throughout, making eight saves to keep his side in the contest for as long as he could. Colombia's best chances came early and often, with Muñoz himself driving a close-range effort into the side-netting before seeing the finish disallowed.
Colombia's pressure ebbed and flowed across a tight contest. Luis Díaz had two goals ruled out by VAR — the first for a foul in the build-up, the second for offside — as the clinical edge that had torn Uzbekistan apart in the opening game proved harder to find against a side that sat deep and defended with collective discipline.
The breakthrough came via substitute Juan Quintero, on for James Rodríguez, who took control of the game's tempo in the final quarter and slipped through the assist that allowed Muñoz to convert with a first-time finish.
Colombia face Portugal on June 27 at Miami Stadium in a game that will determine who tops Group K. DR Congo, on one point from two games, must beat Uzbekistan in their final fixture to keep their World Cup alive.
"We played with intensity and aggression, and we stuck to our style," Muñoz said. "This achievement belongs to the entire team; we earned these three points as a team and for all the fans who came out to support us.
"This victory gives us a morale boost. We don't want to settle for this."
Coach Nestor Lorenzo was measured in victory.
"I want to thank this team for all their effort. They followed the game plan to a T. We deserved a better result; toward the end, our opponent made things difficult for us, but we were the deserved winners."
Congo DR head coach Sébastien Desabre was gracious in defeat, paying tribute to his side's resilience while acknowledging the quality of the opposition.
"It was a difficult match for us. We played against a very good team. They were superior. Our players, as usual, fought on the pitch to get a result, but we couldn't manage. Portugal and Colombia give us a lot of experience that we're faced with, because for us, this is our first World Cup."
Colombia have now won both group games and qualified with a game to spare. Lorenzo's well-organised side have conceded only once in two matches and go into the Portugal decider with confidence and momentum.