Todd Frazier and Ryan Hanigan each had two hits and drove in a pair of runs to back another quality start by Johnny Cueto in the Reds' 5-2 victory over the Diamondbacks.
Cueto (17-6) allowed just two runs on four hits in seven innings to take over sole-possession of the MLB lead in wins. He has won eight of his last nine decisions.
"Every time he goes out there we expect to win," Reds manager Dusty Baker said of Cueto. "He doesn't want to give up anything, that's the kind of guys that we like to be around."
Cincinnati's third win in four games has the club seven games up on the Cardinals in the NL Central race.
Arizona was hoping Wade Miley (14-9) could put the brakes on a four-game slide, but the rookie gave up three runs on six hits over seven innings to take the loss.
Gerardo Parra had two doubles, scored once and knocked in a run in defeat.
Cueto came in with an NL-leading 2.47 ERA while Miley's 2.80 mark ranked fifth in the Senior Circuit.
Cueto blinked early, as Parra led off the Arizona first with a double, moved to third on a wild pitch and scored on Jason Kubel's sacrifice fly.
The Reds answered in their second at-bat by putting their first three hitters on with a walk sandwiched between a pair of singles by Frazier and Chris Heisey. Frazier scored on a wild pitch, and Hanigan knocked in a pair with a single to left field.
"Wade couldn't get the ball down that inning. The balls were elevated and they were hitting them," Diamondbacks manager Kirk Gibson said.
Parra's RBI double in the fifth cut Arizona's deficit to 3-2, but the Reds tacked on two runs against Matt Lindstrom in the eighth.
Lindstrom, acquired for starting pitcher Joe Saunders in a trade with the Orioles on Sunday, gave up three straight hits in his D'Backs debut, the last a two-run triple to the left-field gap by Frazier.
Jonathan Broxton twirled a 1-2-3 eighth, and Aroldis Chapman shook off a leadoff walk in the ninth to record his 33rd save.
Cueto improved to 5-0 lifetime against the Diamondbacks ... Brandon Phillips and Heisey also had two hits apiece for Cincinnati ... Chapman has converted a franchise record 25 straight save chances ... The Reds will look to finish off the three-game sweep on Wednesday with Mat Latos toeing the rubber against Patrick Corbin.