Derek Norris went 3-for-4 with two RBIs and two runs scored for Oakland.
''Just continuing things that I fixed last year,'' Norris said. ''Just trying to stay balanced and make sure you've got your timing going into the season.''
Starter Tommy Milone struggled at times, but lasted five innings and gave up three earned runs on five hits.
''You really want to be as close as you can to game-ready, season-ready this late in the spring,'' Milone said.
Brandon Phillips hit a solo home run, finishing 2-for-3 for the Reds. Phillips has not hit well this spring, but six of his 10 hits have been for extra bases - including five home runs.
Billy Hamilton drove in a pair of runs for the Reds with two sacrifice flies.
Cincinnati benefited from three Oakland errors. Jason Bourgeois reached base twice on errors by shortstop Jed Lowrie and second baseman Eric Sogard and scored. Zack Cozart reached on a throwing error by third baseman Josh Donaldson and scored.
Donaldson had two hits and an RBI and scored twice, and speared a line drive from the Reds' Kristopher Negron in the eighth.
Oakland's bullpen held the Reds scoreless for four innings, with closer Jim Johnson and relievers Luke Gregerson, Sean Doolittle and Andrew Werner pitching an inning each.
REDS: Veteran lefty Jeff Francis allowed five runs on six hits in four innings with five strikeouts and three walks.
''He's a guy that can give us some strong support if needed during the year,'' Reds manager Bryan Price said.
ATHLETICS: Milone is going to be in the A's starting rotation and will next pitch in Saturday's game at San Francisco. He'll get in some work with fellow starter Dan Straily that night.
''It'll be nice to get back out there again even though it will be a shorter day,'' Milone said.
Both the Reds and A's have decisions to make at catcher.
The Reds' Devin Mesoraco has a strained oblique and might not be ready to start the regular season, so non-rostered Corky Miller, who started Tuesday's game, still has a small chance despite his low offensive production. Miller moved a runner to third with no outs that led to the Reds' second run and went hard after a foul pop that he just missed.
Mesoraco is taking swings but not playing games, and is trying to avoid the disabled list and be ready for opening day. Price said he'll have to hit in minor-league games before the season opener.
Oakland has four catchers on the current roster and one of those is the hot-hitting Norris, who is batting .436 this spring. Tuesday's DH was Chris Gimenez, who went 1-for-4, but has the lowest batting average of the four receivers including Stephen Vogt and John Jaso.
Norris said he has incorporated a leg kick in his swing routine and is going up to bat not being afraid of getting jammed.
REDS: Johnny Cueto pitched long into a minor-league game Tuesday afternoon after being scratched from his scheduled start due to shoulder soreness on March 20. He seems to be on track for opening day, though Price stopped short of saying Cueto will get the nod.
''Johnny's going to be ready to make the opening day roster, for sure,'' Price said.
Sean Marshall is scheduled to throw live batting practice on Wednesday as he deals with a sore left shoulder.
ATHLETICS: Outfielder Craig Gentry and relievers Ryan Cook and Fernando Rodriguez were to appear in a minor-league game Tuesday. All three will start the season on the disabled list. Infielder Nick Punto is out for at least the next two days with a tight hamstring.
ATHLETICS: Minor-league left-hander Murphy Smith gets the call for the A's in their Phoenix Municipal Stadium farewell on Wednesday. Opening day starter Sonny Gray is pitching in a minor-league game to stay on track for March 31 when Oakland opens against Cleveland.