"You're not going to have much success if you're not getting hits with runners in scoring position," said Marlins second baseman Dan Uggla. "We need to bring a little more fire. We were a little flat in this series. Not sure why. We need to take it upon ourselves to be more competitive."
The Marlins dropped to 3-15 all time at Great American Ball Park.
The offensive woes overshadowed a solid outing by right-hander Anibal Sanchez, who allowed two runs on five hits in six innings. He walked one and struck out seven, one shy of a career high.
Sanchez (9-8) allowed just four hits through five innings before giving up a two-out, two-run homer by Miguel Cairo in the sixth inning.
"Anibal did a great job keeping us in the game," said Marlins manager Edwin Rodriguez. "He was mixing up his pitches, throwing strikes. I thought he was outstanding."
The defensive highlight of the afternoon was provided by center fielder Emilio Bonifacio, who made a leaping grab to rob Jim Edmonds of a potential two-run home run in the fourth.
"That catch kept us in the game," Rodriguez said.
Replays confirmed that the 5-foot-11 Bonifacio's glove was above the 8-foot right-center-field wall when he made the catch.
"I tried to get close to the wall and get a good jump," Bonifacio said. "I didn't think it was a home run because it was hit so high. But I knew my glove was over the wall when I caught it."
Bonifacio's catch kept the game scoreless until the sixth, when Cairo launched a two-run home run on a 1-1 pitch from Sanchez put the Reds ahead, 2-0.
"I think it was a slider. He left it over the plate," Cairo said. "I was lucky to put good wood on it. I didn't know I hit it that hard. I thought it would go over the left fielder and stay in the park. It went in the bleachers."
Reds starter Homer Bailey (2-2) retired 10 batters in a row in one stretch.
Bailey, who was reinstated from the 15-day disabled list prior to the game, allowed just three hits in six innings while striking out four.
"Homer's got ace potential stuff," Uggla said. "When he's on, he's tough to hit."
With Bailey's pitch count up to 102, the Reds turned to their bullpen in the seventh.
The Marlins loaded the bases against right-hander Logan Ondrusek, but pinch-hitter Chad Tracy struck out swinging to end the inning.
The Marlins had runners on first and third in the first, but Mike Stanton grounded into a fielder's choice to end the inning.
Reds first baseman Joey Votto was ejected in the first by home-plate umpire D.J. Reyburn.
Votto appeared to argue a strike call under his breath as he stepped back into the batter's box with the count 1-2 and was ejected for the fourth time in two years.
Drew Stubbs batted for Votto and doubled off the wall in center. Stubbs remained in the game to play center field. Edmunds moved from center to first base.
For the second consecutive game, the Marlins pressured Reds closer Francisco Cordero in the ninth.
Mike Stanton, who went 2-for-4 to extend his hitting streak to six games, doubled off Cordero on an 0-2 pitch to begin the inning.
But, with runners on first and third, pinch-hitter Donnie Murphy struck out looking to end the game.
Cordero earned his 32nd save.
The Marlins now travel to Pittsburgh for a four-game series looking to improve on what is now a 3-3 road trip.
"We were able to get guys on base and hit the ball hard, but it seemed like it was always right at somebody," Gaby Sanchez said. "Not much else you can do in that situation. I don't feel like we gave in. We kept putting pressure on them, and they made their pitches when they had to."