Sunday proved a searing day in direct sun, and Luke Combs took the Riverfront Stage just past noon, but it was standing room only for the fans assembled. Just as it was for his over-capacity acoustic set at the Radio Disney Stage on Saturday. And as it was during his HGTV Lodge set later on Sunday. And as it was earlier in the week at his genre-crossing Bonnaroo debut. (See a trend here?) Opening with new single "When It Rains It Pours," off his projected Number One country album This One's for You, Combs commanded the Riverfront audience with his big voice and expert song craft. By the time he got to "Hurricane," which he introduced as "my first Number One song, my first Platinum song," the fans were primed. Cell phones raised in hallelujah, the crowd bobbed, pumping fists to his breakout hit. For Combs, this CMA Fest was a star turn of the highest order. J.G.