It was just enough to keep the NL Central leaders rolling.
Miller pitched six solid innings and had an RBI double after Holliday set the tone when he homered in the first for the second straight night, leading St. Louis to a 5-4 victory over the Colorado Rockies on Saturday.
"He's one of the best hitters in the game," Miller said. "When he runs into a ball like that, you know he's got the power. It was a huge home run for us."
Matt Carpenter added a two-run homer in the second for the Cardinals, who have won 12 in a row at home in the final month of the season dating to last Sept. 14. Of their 10 runs in the first two games of this series, seven have come in the first two innings.
The Cardinals are 9-4 this month. They increased their division lead to 3 1/2 games over Pittsburgh, which lost 6-4 to the Chicago Cubs.
Wilin Rosario, Josh Rutledge and pinch-hitter Michael McKenry each drove in a run in the ninth for Colorado. The Rockies had the tying run on second when Pat Neshek got pinch-hitter Rafael Ynoa to fly out for his sixth save in nine chances.
Miller (10-9) and Adam Wainwright, who won his 18th game Friday, combined for 13 strikeouts and no walks in 14 innings. Miller has allowed one run in his last 20 innings over three starts, with a career-best 17 2-3-inning scoreless streak ending on Ben Paulsen's RBI single in the fourth.
Miller has added a quality curveball to his repertoire during the run.
"I threw some that backed up a little bit," Miller said. "But for the most part, I got it over for strikes and got some swings and misses out of it."
Holliday hit his 18th homer to straightaway center off Franklin Morales (6-8). Morales was one strike away from a perfect second when Pete Kozma walked on a full count, Miller followed with his fifth double and Carpenter hit his eighth homer to make it 4-0.
Morales worked six scoreless innings to beat the Padres in his last start and though he's among the league leaders with 24 homers allowed, he had permitted just one in his previous four outings. He needed 28 pitches to get through the first, with just one swing and miss, and gave up four runs in four innings.
"I felt pretty good," Morales said. "I missed two pitches and they got me."
Even with the three-run ninth, the Rockies have totaled seven runs during a five-game losing streak. They entered the game batting .318 at home with 108 homers and .227 on the road with 60 homers.
"There were a few things we didn't execute on both sides of the ball," manager Walt Weiss said. "In the end, it cost us."
Rockies: 1B Justin Morneau did not start after straining a side muscle on Friday. He is day to day.
Cardinals: Michael Wacha has struggled to regain his form after a shoulder injury sidelined him for nearly two months, and he will not start Sunday. The team is hoping a little rest will help the 23-year-old right-hander.
Rockies: Jordan Lyles (6-2, 4.20 ERA) won his first start after coming off the DL from a broken left hand, but is 0-1 in six starts since then. He pitched six innings of one-run ball in a no-decision at the New York Mets in his previous start.
Cardinals: Rookie Marco Gonzales (2-2, 5.01 ERA) makes his fifth career start after backing up Wacha's two abbreviated starts since coming off the DL. The Cardinals also are skipping John Lackey, announcing after the game that Lance Lynn, Wainwright and Miller would face division rival Milwaukee from Tuesday through Thursday.