Indians starter Justin Masterson gave up Cincinnati's first five runs on four hits over four innings, walking two and striking out six.
Paul hit a 2-2 pitch to center field for a three-run homer, his second long ball of spring, following back-to-back singles by Zack Cosart and Joey Votto. Jay Bruce followed with a walk before Frazier hit his second homer of the spring with a two-run shot to left field that made it a 5-0 game.
Reds starter Mat Latos pitched five innings and allowed three runs (two earned) on six hits with no walks and three strikeouts. Latos, who had struggled in the early going of his earlier outings, retired six of the first seven batters he faced, allowing only a Matt Carson single in the second inning.
"It's just being comfortable in the first inning," Latos said. "It's Spring Training all over again -- you get anxious, nervous and excited all at once. Today I just tried to settle down and throw the baseball, hit my spots and locations. Everything worked really good today. My curveball felt really good coming out of my hand, and my changeup was something I've been working on."
Luis Hernandez led off the third with a single before Brian Jeroloman reached on first baseman a fielding error by Votto. After Michael Bourn grounded into a double play, Hernandez scored on Drew Stubbs' infield hit to shortstop.
The Indians scored twice in the fourth on an RBI double by Chris McGuiness that brought home Cord Phelps and a Juan Diaz groundout to shortstop that plated Carson. Diaz added another run in the sixth with a sacrifice fly against Pedro Villarreal.
Cincinnati padded its lead with back-to-back homers in the seventh from Chris Heisey and Dennis Phipps against reliever Cody Allen before the Indians launched their rally in the ninth.
Up next for the Reds: The Reds will head to Scottsdale on Monday for a 10:10 p.m. ET game against the Rockies, available on Gameday Audio. Bronson Arroyo will get the start and be followed by J.J. Hoover and Clay Hensley. It will be an opportunity for Frazier to continue his hot streak after homering against Cleveland to give himself four extra-base hits in his past six games.
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.