Arroyo (15-10, 4.57 ERA) minimized the damage against him. The Cardinals' two home runs -- Troy Glaus' in the second and Aaron Miles' in the seventh -- were both solo shots.
Retiring 11 of his first 13, Arroyo had more than one baserunner on just once in the game after a pair of two-out singles in the fourth.
Cardinals starter Braden Looper (12-13) was even better in the beginning, as he retired his first nine batters in a row and 15 of his first 16. The Reds were trailing, 1-0, when Arroyo singled with one out in the sixth. Then, with two outs, Jerry Hairston Jr. hit a single to right field, and Joey Votto walked to load the bases. That put Edwin Encarnacion in position to line a bases-clearing double into the left-field corner for the go-ahead runs.
After Miles' homer in the top of the seventh made it a one-run game, pinch-hitter Danny Richar beat out a potential double-play ball on the ground to second base as Corey Patterson scored in the bottom half of the inning. In a three-run Cincinnati eighth, where nine men batted, Patterson added a two-run double with the bases loaded against Ron Villone.
The Reds have won three in a row and six of their last eight. St. Louis, sliding quickly out of the National League Wild Card hunt, has dropped six in a row.
Back on June 24 at Toronto, Arroyo dropped a third-straight decision, but it was no ordinary loss. The Blue Jays shelled him for 10 earned runs over one-plus innings for a 14-1 drubbing. His record following the game was 4-7 with a 6.52 ERA.
"Sometimes you're not proud of how you're pitching," Reds manager Dusty Baker said. "Sometimes it wakes you up."
Arroyo has mostly made good music since. Over his last 15 starts, he is 11-3 with a 2.88 ERA, and he's 5-0 with a 1.45 ERA over his last six starts.
What changed? Arroyo said it was less of a wake-up call and more staying ahead of the scouting reports. He changed the grip on his sinker a few starts after the Toronto game.
"After these guys see me for a long time, it always becomes a big ol' chess match," Arroyo said. "You can almost see their guy at the plate thinking and guessing if it's going to be a fastball away or breaking ball away. Me being able to bring something new to the table the last couple of months -- I can see the look on guys' faces when they're swinging and missing on my sinker. I really haven't thrown that pitch on a consistent basis since 1996 or '97 in the Minor Leagues. To have command of that and get some good movement has helped me tremendously."
In 2005 with Boston and in 2006 with Cincinnati, Arroyo was a 14-game winner. Last season, he dipped to 9-15 with a 4.23 ERA. But he's worked 200 innings in each of the last three seasons.
Had he not been opposed by the dominant CC Sabathia last week in Milwaukee and victimized by a blown save, Arroyo might have had a 16th win. As luck would have it, his next start falls on Sunday vs. Sabathia and the Brewers.
At 187 innings and 18 quality starts, Arroyo's two other goals -- 200 innings and 20 quality starts -- are reachable. At least 15 wins are in the books.
"I didn't want it to come down to have to try to beat Sabathia again," Arroyo said. "You never want to leave it to the last game of the season. I have two left, and it's nice to have a little bit of breathing room to not have to worry about it."