CINCINNATI -- Ryan Ludwick has tried to remain patient since returning from the disabled list. On Monday night, the Reds left-fielder felt like he'd made some significant strides.
"I felt like I had a chance tonight," he said.
Ludwick delivered a key RBI double during a three-run fourth inning, and third baseman Todd Frazier homered, lifting Cincinnati to a 5-3 victory over the Arizona Diamondbacks in the opener of a four-game series at Great American Ball Park.
It was the first RBI of the season for Ludwick, who missed more than four months after injuring his shoulder on Opening Day.
"I wanted it all at once," Ludwick said. "Baby steps. It's a process. The guys have been patient with me. I felt like I had my rhythm tonight. Overall, today was a positive."
Second baseman Brandon Phillips went 3-for-4 with a triple and two runs scored as the Reds increased their lead to six games over Arizona for the National League's second wild card spot.
Cincinnati has won 12 of its past 17 games.
"I feel like our best days are ahead of us," said Reds manager Dusty Baker.
Reds starter Bronson Arroyo (12-9) was sharp enough to earn the victory, allowing three runs on seven hits with no walks and six strikeouts in his team-leading 18th quality start.
"I didn't feel like I had my best stuff," Arroyo said. "Some nights you feel like you could run a marathon, then you hit a wall. The offense put up some runs to keep the momentum."
Aaron Hill hit his ninth home run in the fourth inning for Arizona.
With the bullpen taxed after this past weekend's grueling series in Pittsburgh, including a 16-inning game on Sunday, the D-backs needed innings out of starter Randall Delgado.
Although he took the loss, Delgado (4-4) battled for six innings, allowing five earned runs on seven hits with three walks and six strikeouts over his career-high 114 pitches.
"He did a good job all in all," said Arizona manager Kirk Gibson. "If you watch Randall this year, he keeps his composure. He toughed it out."
With the Reds leading 5-1, Arizona loaded the bases against Arroyo with one out in the sixth. Martin Prado's two-run single cut Cincinnati's lead to 5-3. But, Arroyo was able to minimize the damage.
Cincinnati's bullpen took over from there. J.J. Hoover struck out two batters in the eighth to extend his scoreless streak to 26 1/3 innings.
"They're strong right now," said Baker of his bullpen, which hasn't allowed a run in eight of its last nine appearances.
The Diamondbacks had the tying run on base in the ninth against Reds closer Aroldis Chapman. But a double play helped Chapman earn his 31st save.
The Reds took the lead in the second inning. Phillips tripled and scored on Zack Cozart's major-league-leading ninth sacrifice fly, putting Cincinnati ahead 1-0.
Arroyo allowed two singles in the first inning, then retired the next nine batters he faced, before Hill tied the score 1-1 in the fourth with a line-drive home run to left.
Cincinnati began to square up Delgado's pitches in the fourth. Four consecutive hits, including an RBI single by Jay Bruce and the RBI double down the left-field line by Ludwick, put the Reds ahead 3-1.
"He got a ground ball just out of the reach of Prado," D-backs manager Kirk Gibson said of Ludwick's double. "We could have gotten a double play and been out of it."
Frazier's solo home run on Delgado's first pitch in the fifth inning made the score 5-1.
"We just missed some balls down the middle," said D-backs catcher Wil Nieves of Delgado. "You miss with some fastballs down the middle and they're going to put some hits together."
NOTES: Diamondbacks C Miguel Montero, who's on the disabled list retroactive to July 29 with a lower back strain, was expected to catch 3-5 innings Monday night on a rehab assignment with their Arizona League affiliate. Montero went 1-for-5 with a walk and two runs in his first two rehab games. His rehab is expected to last through Saturday, when he'll be reevaluated. ..D-backs CF Adam Eaton is a graduate of Miami (Ohio) University and native of Springfield, Ohio. .. Reds LHP Sean Marshall, on the DL since May 24 with left shoulder tendinitis, resumed his throwing program on Monday. There is no timetable for his return. .. Arroyo hasn't allowed the first batter to reach base in any of his 25 starts. .. Phillips' triple was his first since April 28 of last season. .. Hill's home run extended his hitting streak to 12 games. .. Delgado dropped to 0-3 lifetime vs. Cincinnati. .. Reds left-hander Manny Parra made his fifth straight scoreless appearance.