The win keeps St. Louis a half-game behind National League Central-leading Cincinnati, winners over the Cubs earlier in the day.
The Cardinals improved to 14-7 since the All-Star break and move to a season-best 13 games above .500 for the third time this season.
The Cardinals staked Wainwright to an early 3-0 lead when Pujols drilled a three-run homer into the left-center-field seats in the top of the first inning. Pujols' 28th home run of the season came on a 1-1 pitch from Marlins starter Ricky Nolasco, with Felipe Lopez and Jon Jay aboard.
Pujols has now hit a home run in five of his last six games and moved to within six roundtrippers of the 400 milestone. It's also Pujols' 74th homer in the month of August, the most of any month during his career. Pujols also had a double and single and drove in four runs. His home run was another one of his patented line drive, tape-measure shots.
"That was the same stroke he used all night long," Cardinals manager Tony La Russa said of Pujols' home run. "I was telling [hitting coach] Mark [McGwire] that was exactly the stroke that Mark used to use. That was just classic hitting right there."
La Russa described Wainwright's performance as "masterful, artistic," and indeed it was.
Only an infield single by Marlins shortstop Hanley Ramirez in the bottom of the third inning and a bloop single just beyond the reach of St. Louis shortstop Brendan Ryan in the eighth kept Wainwright from registering a no-hitter. La Russa labeled it an "unofficial no-hitter" after the game.
Wainwright smiled and laughed when told of La Russa's comment.
"I don't feel like there is such a thing, but out of respect for my manager, I'll say yes," Wainwright said.
The lanky right-hander went the distance for the fifth time this season. He registered seven strikeouts and issued three walks to improve his record to 16-6. Seventy-one of Wainwright's 110 pitches were strikes and he lowered his ERA to 2.07.
"He had everything working," La Russa said of Wainwright, who is 15-0 when receiving four-plus runs this season. "Every time a hitter came up, the hitter saw something different."
Wainwright didn't need much run support on this particular night, but the Cardinals' bats supplied plenty of hitting throughout the lineup.
Six of the Cardinals' 13 hits were doubles, including two by Aaron Miles, who was a late substitution at second base for Skip Schumaker. The Cardinals had four doubles in a three-run fourth inning that gave Wainwright a comfortable 7-0 lead. That was plenty of run support for Wainwright, who entered the game with a sparkling 2.19 ERA, third-best in the NL.
By the middle of the fifth inning, the only Cardinal who had not reached base was Wainwright -- and even he contributed at the plate by laying down a sacrifice bunt in the fourth. The Cardinals touched Nolasco for 10 hits and scored all seven runs off the Florida right-hander, whose record dropped to 12-8.
Pujols and Jay, who played college ball at the University of Miami and had a contingent of family and friends in the audience, each had three hits for St. Louis, which improved to 61-48. It's Jay's fifth three-hit game this season. Miles and Ryan, the No. 7 and 9 hitters in the lineup, each contributed two hits.
"I think it was a great team win," Wainwright said. "Everybody did exactly what they're supposed to do. Our offense scored runs on a very tough pitcher, and I held the other team down, so it was a good win. Ricky Nolasco is a very tough pitcher. He's got amazing stuff, so you get a couple of runs on a tough pitcher like that early on, it makes things really good."
Wainwright said he felt that everything was "clicking" for him on the mound. The only time in the game that it appeared things weren't clicking was in the bottom of the fifth, when he walked the first two Marlins batters. He pitched out of the jam by retiring the next three batters.
"Adam was Adam Wainwright," Pujols said. "He was perfect, pretty much."
None of the Marlins would argue with that assessment.
"Tonight, he was outstanding," Marlins third baseman Wes Helms said of Wainwright. "Changing speeds, working both sides of the plate. He kept everybody off-balance. Tonight, he had his stuff."
Steve Dorsey is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.