Maykel Reyes had got the islanders a lead after just seven minutes, but a penalty from Kwon Changhoon levelled the match, before Ryo Seungwoo gave the experienced U-20 nation a deserved win to open Turkey 2013.
It was an early corner that saw Cuba get off to the perfect start. Reyes rose at the back post to head home after goalkeeper Lee Changguen raced off his line in vain, though Sim Sangmin came achingly close to clearing the effort off the line.
It took Korea Republic until the half hour-mark to find their feet, but from then on they had Cuba rattled. They maybe should have drawn level when Cho Sukjae, Ryu Seungwoo and Kang Sangwoo all spurned good opportunities in quick succession to leave the east Asians trailing at the break.
The trend continued as Sukjae had another effort two minutes into the second period, firing wide after a bursting run. However, they did not have to wait long to equalise, as Reyes cancelled out his fine work earlier on by bringing down Sangmin in the penalty area, allowing Kwon Changhoon to score from 12 yards.
The game was then wrapped up when a delightful one-two between Sangwoo and Seungwoo saw the latter smash the ball home from eight yards.
Abel Martinez almost earned a last-gasp point for the debutants with an audacious long-range effort in stoppage time, but a thankful Changguen watched it sail narrowly over the bar.