Hayes, bidding for the backup catcher's job, connected on an 0-1 pitch from right-hander Jeff Stevens. The Royals' record improved to 7-0-1; the Reds are 2-7.
Both starting pitchers made their first starts in the Cactus League and each got through two scoreless innings. The Royals' Ervin Santana retired the first five batters, then survived a walk and Chris Heisey's double. He worked out of the jam with a strikeout and finished with a pitch count of 31, including 18 strikes.
"Everything was very good," Santana said.
The Reds' Mat Latos walked the first two batters he faced in the first inning and also pitched past a second-inning double by Xavier Nady. Latos felt like he made the right adjustment in the second inning.
"I stayed on a straight line," Latos said. "Throwing in the first inning with a little adrenaline, I kind of opened up the front shoulder a little bit."
Cincinnati's Devin Mesoraco began a flurry of solo home runs in the fifth inning with a homer to left off Greg Holland. Chris Getz countered by leading off the Royals' fifth with a blast to right field against Sam LeCure. Kristopher Negron came right back, opening the Reds' sixth with a first-pitch blast off Aaron Crow.
Miguel Tejada's double and Salvador Perez's RBI single pulled the Royals even, 2-2, in the sixth.