CINCINNATI (Ticker) -- This time the Cincinnati Reds kept an impressive effort by Chris Reitsma from going to waste.

Reitsma (3-0) pitched a season-high 7 2/3 innings, allowed one earned run and struck out six as the Reds posted a 6-1 triumph over the Florida Marlins.

In his last start, Reitsma allowed just one run on four hits in seven innings against the Milwaukee Brewers, but left with the game tied. On Tuesday, Reitsma escaped a bases-loaded jam in the fourth inning to preserve a 1-1 tie, then retired 13 of the next 15 batters.

"You tell yourself you have to execute," Reitsma said. "You try to go as hard as you can as long as you can. You know what to do, (but) it's a matter of doing it. I knew it last year but I had to learn to trust myself enough to (execute)."

Reitsma has not allowed more than one earned run in four of his last five games for the Reds, who are 7-2 when he starts.

"He's been our most consistent pitcher," Cincinnati manager Bob Boone said. "Last year he knew what he had to do, but his mistakes happened and he lost focus. Sometimes as a manager, you have to suffer through that. His heart is off the charts. He's motivated. He worked hard over the winter and is a lot stronger this season."

The Reds broke open the game with five runs in the fifth inning. Sean Casey put Cincinnati ahead, 2-1, by plating Barry Larkin with a single to left. Austin Kearns provided insurance with his first career grand slam.

"It was nice to get one (grand slam)," Kearns said. "I don't think I've hit one in pro ball. Maybe in high school or summer ball."

Todd Walker had two hits and a run for the Reds.

Florida starter A.J. Burnett (5-4) gave up six runs and five hits in five innings. He struggled with his control, walking four.

After holding opponents to four runs or less in seven of his first eight outings, Burnett has surrendered at least five runs in each of his past two starts.

Burnett's problems began in the second inning when he walked in Cincinnati's first run. Kearns opened the inning with a flyout but Walker doubled to left. Burnett got Aaron Boone to strike out for the second out.

The Marlins intentionally walked Corky Miller to get to Reitsma, who fouled off four pitches before drawing another walk to load the bases. Burnett then walked Larkin, scoring Walker.

"First of all, I throw a 2-2 curveball to (Reitsma)," Burnett said. "I should go right at him. The guy is hitting zero, I think. I just couldn't find it (control) all night."

Burnett faced a similar situation in the fifth after surrendering base hits to Juan Encarnacion and Casey then loading the bases with a walk to Adam Dunn. Burnett got behind in the count, 3-1, before tossing a fastball which Kearns blasted over the left field wall.

"That's the kicker, the walks," Burnett said. "The guy hits the grand slam and that (stinks), but the five walks. If I make pitches and get ahead, the pressure is on him. But I didn't so the pressure was on me."

"I made up my mind that I was going to take another pitch," said Kearns, who was given the green light on a 3-0 count. "The more pitches you see, the better. I figured he would throw me a fastball. It's his best pitch and the one he can throw for strikes."

The Marlins, who have lost five of their last six games, had an opportunity to take advantage of another bases-loaded situation in the eighth but Reds closer Danny Graves got Charles Johnson to ground out to end the inning.

Florida scored its lone run in the third inning.