But it wasn't.
Colin Rea, who was making his Marlins debut after being acquired in a trade with the San Diego Padres, left after 3 1/3 innings because of soreness in his right elbow.
Marlins doctors will evaluate Rea, but, for now, it is cause for concern.
"We obviously needed the win," Marlins reliever David Phelps said. "But not at that cost."
Further complicating things for Miami is the fact that starting pitcher Wei-Yin Chen is already on the disabled list because of an elbow injury that occurred Monday.
"Hopefully it's nothing," Phelps said of Rea's injury. "But you never like to see a starter come out of a game, especially when you are strapped for starters to begin with."
Rea pitched well before his injury, retiring 10 of the 11 batters he faced, including four by strikeout. He allowed no runs, just a soft single in the third.
But after striking out Jedd Gyorko leading off the fourth inning, Rea motioned to the trainer, and that was the end of his Marlins debut.
"He was still locating," Marlins catcher Jeff Mathis said when asked what he saw in Rea. "But (the ball) just wasn't coming out as hard as it was in the first two innings. It is unfortunate."
Phelps (5-5) replaced Rea and picked up the win as the Marlins (56-48) tied the Cardinals (56-48) in the race for the second wild-card playoff berth. Miami goes for a split of the four-game series Sunday.
St. Louis' Jaime Garcia, who was 2-0 with a 1.99 ERA in five previous starts against the Marlins, took the loss.
Garcia (7-8) allowed seven hits and six runs in 3 1/3 innings.
Miami pounded out 12 hits overall, three apiece by Christian Yelich and Mathis. Marcell Ozuna had the biggest hit, a two-run homer, as the Marlins improved to 4-5 on the 10-game homestand that ends Sunday.
But even with all those Marlins hits, none came off the bat of Ichiro Suzuki, who needs two more to reach 3,000.
The Marlins' 42-year-old cult hero entered the game as a defensive replacement and went 0-for-2 against journeyman reliever Jerome Williams, who is on his eighth major league team.
Suzuki, who hit a routine fly out in the eighth, had his best chance at a hit in the sixth. With runners on second and third and the infield in, Suzuki grounded out to first.
"I know he needs two more hits," Williams said of Suzuki's chase of 3,000. "I told myself, 'I don't want to be that guy.' I just tried to get him out anyway possible."
Miami started its barrage early.
The first five batters in the Marlins' half of the first inning made hard contact, starting with a Dee Gordon double that went over the head of Cardinals center fielder Tommy Pham. Yelich had an RBI double, and Giancarlo Stanton hit a run-scoring single before Ozuna hit his two-run blast to left.
It was Ozuna's 19th homer of the season.
Miami made it 8-0 with four runs in the fourth. Mathis hit another double over the head of Pham, scoring when Adeiny Hechavarria's double went off the glove of left fielder Matt Holliday.
The Marlins capped the inning when Martin Prado bounced a two-run double just inside the third-base line, and Yelich pulled an RBI single to right.
Miami closed the scoring with three runs in the sixth off of Williams, who hit Chris Johnson with the bases loaded and then allowed a two-run single by Mathis.
"The game didn't go the way we wanted from the beginning," Cardinals manager Mike Matheny said. "Then it was just a matter of trying to survive."
NOTES: Cardinals C Yadier Molina extended his hit streak to 14 games. ... Miami optioned RHP Jose Urena (1-3, 6.69 ERA) to Triple-A New Orleans and called up RHP Brian Ellington from the same team. Ellington, who had a 0.79 ERA in 11 1/3 innings with the Marlins earlier this season, will again work from the bullpen. ... Miami also designated OF Cole Gillespie for assignment. ... Miami RHP Andrew Cashner, acquired Friday in a seven-player trade with the San Diego Padres, is set to make his Marlins debut in Sunday's series finale. St. Louis counters with RHP Carlos Martinez. ... Cardinals 1B Brandon Moss (sprained left ankle) and 3B Jhonny Peralta (left thumb) are set to return from the disabled list by Tuesday's game at the Cincinnati Reds. ... Cardinals 2B Matt Carpenter (right oblique) will begin a rehab assignment Sunday at Double-A Springfield. He's due back Friday.