Updated

Another poor offensive showing turned the defending NL Central champions into a break-even team.

Ian Kennedy overcame a nasty spill and pitched into the sixth inning before his ankle stiffened on Wednesday night, leading the Arizona Diamondbacks to a 3-1 victory that dropped the Cincinnati Reds to .500 for the first time since May 8.

Kennedy was the key to the Diamondbacks' third straight win. Kennedy also had a run-scoring groundout off Bronson Arroyo (2-2), who got little help from a struggling offense.

The Reds have lost six of seven, falling to 9-9. The last time they had a break-even mark was 30 games into last season.

"As long as we don't panic and continue to work hard, it'll be great," manager Dusty Baker said. "I'm as positive as I've ever been. I'm not happy, but I'm positive."

The Reds' offense was rolling at top speed when they opened the season with five wins. They got off to their best start since 1990 even though they were missing two starting pitchers with Homer Bailey and Johnny Cueto sidelined by shoulder problems.

With the offense drying up, that early momentum has vanished.

"You keep plugging away," Baker said. "I try to be more positive. People want you to yell at them and kick them, but that makes them feel worse. Nobody feels worse that those guys, but there's a whole bunch of ball left. People got spoiled by our start, but even when we were winning, we weren't whole."

For the third game in a row, the Reds had trouble putting hits together. They've managed only 13 hits in the last three. J.J. Putz got his fifth save in five chances, needing only seven pitches in a perfect ninth.

Justin Upton had a sacrifice fly, and Ryan Roberts added an RBI double off Arroyo, who retired 15 batters in a row after another slow start.

Willie Bloomquist and Kelly Johnson opened the game with doubles, and Upton's sacrifice fly made it 1-0. The Reds have been outscored 22-12 in the first inning this season, by far their worst.

Stephen Drew doubled and scored on Kennedy's groundout in the second, starting a streak of 15 straight batters retired by Arroyo — an indication he's getting back to normal after coming down with mononucleosis during spring training.

"They got to me early on with a couple of runs," Arroyo said. "That was something you try to avoid. When you're in a rut like this, you want to start with a lead first. I made a couple of adjustments. I tried to slow things down and simplify things. I tried to play a mental chess game with them.

"We just weren't able to get anything going. We're just not getting the big hits right now."

Roberts doubled home a run in the seventh for a 3-1 lead, ending Arroyo's outing.

"Arroyo did a good job," Arizona catcher Miguel Montero said. "Fortunately we got a couple of hits in good situations. And Ian was on."

Kennedy handled the Reds in Arizona on April 8, allowing one run and six hits over eight innings in a 12-2 victory. He was tough on them again Wednesday, giving up four hits, including Joey Votto's run-scoring double in the sixth.

Kennedy overcame a nasty tumble in the fifth, when one of his pitches came right back at him.

Jay Bruce's grounder smacked off the outside of Kennedy's lower right leg during his follow-through. The shot knocked the leg out from under him, leaving him sprawled on his back. The ball deflected into foul territory for a single.

A trainer checked the leg, and Kennedy threw several practice pitches. He struck out the next batter, Jeremy Hermida. When he went to the bench, the ankle started swelling. He left after giving up Votto's RBI double in the sixth.

NOTES: Arizona 3B Melvin Mora missed his second straight game with a sore left foot. ... Bailey will have his next rehab start pushed back a couple of days because of stiffness. Bailey threw five scoreless innings for Triple-A Louisville on Sunday. He was expected to start again on Friday, but will get a few extra days to recover. ... Cueto will make his second rehab start for Louisville on Thursday.