During the streak, the Reds have beaten Arizona and earned back-to-back three-game sweeps over Milwaukee and at Houston. Colorado has now dropped four of its past five games and nine of 13.
Meanwhile, the Reds have won 15 of their last 17 games and are 9-2 since Joey Votto went on the disabled list.
"Things are kind of roiling our way right now," Arroyo said. "There are other guys in our division that are obviously playing as good or close to it. It's not like we have a huge gap. We just have to keep grinding and keep getting after it."
The only thing the Reds haven't done lately is put distance between them and the Pirates. Pittsburgh beat Houston on Friday to stay two games behind in the NL Central.
No problem, says Phillips.
"We're trying to get as many wins as possible," Phillips said. "Once you think about winning instead of worrying about what other teams are doing, the only thing that can really stop you is yourself. We're staying consistent as a team. We're having fun. It's fun winning and it's nice to see everybody come together."
Arroyo gave up six hits with no walks and three strikeouts over 6 2/3 innings for his third victory over his past four starts. He's improved to 6-6 with a 3.76 ERA in 20 starts.
"He's a good pitcher," Rockies third baseman Jordan Pacheco said. "He's been around a long time and knows how to pitch. He kept us off balance all night."
It was scoreless until the Reds broke through against Rockies lefty Drew Pomeranz in the fourth. Following a leadoff single, Phillips advanced to second base on a flyout. Phillips scored when Ryan Ludwick lined a double down the left-field line. Ludwick made it 2-0 when he scampered home from third base on Todd Frazier's sacrifice fly.
Pomeranz gave up a pair of one-out singles to Ludwick and Scott Rolen in the sixth and watched his bullpen give up another run. Reliever Adam Ottavino threw a pair of wild pitches to Frazier, the second one letting Ludwick score from third base for a three-run lead.
It was more than enough for Arroyo, who retired his first 11 batters in a row before giving up a hit. Not a bad beginning for someone who came in 0-2 with an 8.84 ERA lifetime at Coors Field.
"He's a breaking-ball pitcher that throws every pitch. It's tough here sometimes because breaking balls don't break here," Reds manager Dusty Baker said. "I've seen the best of breaking-ball pitchers have a tough time here and he's had a tough time here. I'm glad we got him back to 6-6. Hopefully he can get on one of his extended streaks of wins."
Colorado threatened in the fifth, with Pacheco's one-out double putting runners on second and third base. Arroyo struck out Josh Rutledge and in a curious move, the Rockies let Pomeranz bat for himself before he grounded out to first base. Pomeranz was pulled in the sixth after facing three batters.
Arroyo gave up a one-out single and a two-out single in the seventh before coming out with only 85 pitches. He had put the Reds dugout on notice that he didn't have much left in the tank, and Cincinnati had someone warming up.
"In this atmosphere, a couple of times I had to run hard," Arroyo said. "I felt like I was getting the shakes a little bit. I didn't want them to be surprised because my pitch count was so low."
Alfredo Simon took over and worked out of the jam with a popout. Simon returned for a scoreless eighth and escaped after a one-out double into the wind in left field by Marco Scutaro. Aroldis Chapman struck out the side in the ninth, with one hit allowed, as he threw 10 of 11 pitches for strikes to earn his 20th save.
Baker marveled at the fact the Reds pulled off a shutout at Coors Field.
"I can't tell you the last time I was on a team that shut these guys out in Colorado. That doesn't happen very often," Baker said. "Everybody is pulling on the same end of the rope. Everybody is doing their job. Daily, we have different guys come through."