A loss would have put the Rockies at a too-close-for-comfort 3 1/2 games out of the National West lead, with the Giants lurking at only 4 1/2 back.
"We gave [Billingsley] a five-run cushion, and you know, it was a big game for us -- for a lot of reasons," Dodgers manager Joe Torre said. "Winning a ballgame for one, and of course, getting Billingsley back."
After missing his last scheduled start because of a strained left hamstring, Billingsley tested his newly healed leg from the get-go.
The Cardinals' leadoff hitter, Skip Schumaker, hit a grounder back to Billingsley in the top of the first, but Billingsley easily scooped up the ball and tossed it to first for the out.
Billingsley hit 94 mph on the gun later in the inning to further prove that he felt fine on the mound.
And with the leg no longer an issue, Billingsley returned to the strong form he displayed the past two starts in which he allowed just one earned run on six hits in 11 combined innings. On Tuesday, he allowed two runs on three hits over six innings.
Billingsley cruised through the first five innings, allowing just one hit and walking none.
"I really didn't know what to expect today," Billingsley said. "I had command of my fastball, and I threw that a lot today. I mixed in some offspeed, and I was really pleased with how I threw the ball."
While the Cardinals rarely forced Billingsley out of his comfort zone, the Dodgers' offense consistently forced St. Louis starter Mitchell Boggs to work out of the stretch.
The Dodgers put at least one runner on base in each of the first five innings and broke through in the fourth after stranding five runners through three innings.
In the fourth, the Dodgers peppered Boggs for two runs on four consecutive hits, beginning with a screaming line-drive double to deep center field by Russell Martin.
One of those RBI hits belonged to Billingsley, who successfully ran to first base without injuring his hamstring. Billingsley strained his hamstring on Aug. 7 after singling in the sixth inning.
"I was just taking it easy when I was on the bases," Billingsley said. "[First-base coach Mariano] Duncan and [third-base coach Larry] Bowa were motioning, telling me to take it easy, not run that hard."
The Dodgers scored three more in the fifth after Andre Ethier led off the inning with his third triple of the season to begin another streak of four straight hits.
By the end of the inning, the Dodgers had totaled 11 hits from eight players. For the game, all nine starters registered at least a hit apiece and seven recorded an RBI.
Ethier was 3-for-4 with a walk and finished a homer short of the cycle.
"We got to their guy a little bit earlier tonight, and we stayed on top," said Orlando Hudson, who also went 3-for-4 with an RBI. "We drove in some key runs early on, which is definitely a good thing, and we haven't been doing that lately."
The Cardinals cut the Dodgers' lead to 5-2 in the top of the sixth, but they could have made the game much tighter than a three-run affair.
Billingsley hit St. Louis catcher Jason LaRue to lead off the inning and pinch-hitter Joe Thurston doubled down the right-field line to set up the top of the Cardinals' lineup.
After a groundout plated St. Louis' first run of the game and Brendan Ryan drove in Thurston, Albert Pujols came up with one out, a runner on first and the Cardinals trailing, 5-2.
But Billingsley held strong and got Pujols to ground to third baseman Casey Blake to start an inning-ending double play.
That was the final pitch Billingsley threw Tuesday as Torre turned to the bullpen to close out the game. Billingsley threw 77 pitches total, and Torre said that the club was looking for him to throw between 80-90 pitches.
"He hadn't been out there in a little bit," Torre said.
But given the state the Dodgers' starting rotation has been in of late, six innings of two-run ball is a positive sign that Billingsley could provide some much-needed stability to the staff.
"It was a big win," Hudson said, "Billingsley came out and threw a great game."