Returning to Miami was a relief for the Marlins after dropping all six games on their road trip to Atlanta and Philadelphia.
"After we came back, we thought we should forget about that and focus on what we should do right now and execute in the game," Chen said through an interpreter. "Everybody played great. I think it was a great team win."
Kyle Barraclough's struggles continued as he was unable to secure the save in the ninth, allowing one run on two hits and two walks in one-third of an inning. But Javy Guerra came in to shut the door, earning his first save of the season by escaping a one-out, bases-loaded jam with a double play off the bat of Yadier Molina.
"You see the at-bats from their side," Marlins manager Don Mattingly said. "They're a team that's fighting for survival. In their at-bats, you can see it. You can see that kind of fight in there, because this time of year, you can't lose games. You don't want to lose any games."
Starlin Castro delivered his ninth home run of the season, crushing a hanging changeup into the bleachers in left in the fourth off Cardinals right-hander Luke Weaver. The Marlins got their other run on Brian Anderson's check-swing RBI single in the first.
Chen was lights-out, striking out four, walking two and keeping St. Louis' lineup at bay with the usage of all five of his pitches, especially his offspeed. According to Statcast™, of Chen's 91 pitches (54 strikes), 33 were sliders and 13 were curveballs, accounting for 10 of the 15 balls the Cardinals put in play. The lefty threw 37 four-seam and three two-seam fastballs.
"Throwing offspeed pitches hasn't been my thing in the past," Chen said. "Tonight, I did it well. I think there's a lot of things I still need to learn and work on."
Chen faced the Cardinals in St. Louis on June 6 and was lifted after giving up two runs in 4 1/3 innings and 91 pitches. He allowed six hits and his share of hard contact, which led to him going more with offspeed pitches.
"I've faced them before and they've hit me pretty well in the past," Chen said. "I needed to make some adjustments. I had a pretty good combo with J.T. [Realmuto]. He's been calling great pitches behind the plate. Tonight, I needed to make some adjustments."
The lone hit that Chen surrendered came in the second to Marcell Ozuna. Just moments after stepping into the box at Marlins Park for the first time since being traded to St. Louis in the offseason, Ozuna smashed a base hit to left, registering at 112.1 mph per Statcast™. Ozuna finished 3-for-4 with three singles against his former team.
Chen's pitching splits between home and the road have been night and day in 2018, and the numbers speak for themselves.
In nine outings away from Marlins Park, Chen is 1-6 with an ERA of 10.27. After Monday's strong performance, the southpaw's home ERA dropped to 1.94 (11 runs in 51 innings).
Home and road splits aside, the impetus for Chen's impressive outing Monday was his mix of pitch speeds, tossing 51 offspeed to 40 fastballs.
"Each game is a different animal with different guys," Mattingly said. "Certain guys, you're going to throw more breaking balls to. You may get a team where the backdoor breaking ball or the changeup is a better pitch for you that night. Most of the time, the matchup you get is the way you're going to pitch within your stuff."
MOMENTS THAT MATTERED With the Marlins up 2-0 in the ninth, Mattingly called upon Barraclough to secure the save. Miami's closer had blown three consecutive save opportunities, and his struggles continued.
Paul DeJong led off the frame with a sharp single to center and Harrison Bader followed with another base hit to right. Barraclough then lost his command by walking Yairo Munoz on four pitches after he showed bunt.
After striking out pinch-hitter Kolten Wong looking on a backdoor breaking ball that barely clipped the outside corner, Barraclough walked Matt Carpenter to force in the Cardinals' first run. That was enough for Mattingly, who made the call to the bullpen and gave the ball to Guerra.
"Javy is not necessarily a ground-ball guy, but at that point, I'd seen Javy work," Mattingly said. "He saved 20 straight games for me in L.A., and I've seen him be in bases-loaded jams with nobody out and get out of them. So I know he's a guy who's not going to panic."
Guerra did his job, inducing a tailor-made double-play ball from Molina on just the second pitch he threw.
SOUND SMART Guerra's save marked his first since Sept. 27, 2014, when he was a member of the White Sox.
The eight-year veteran reliever said after the game that his mentality entering a high-leverage situation is no different than the less pressure-filled relief opportunities he has become accustomed to of late.
"You've got to treat it the same," Guerra said. "You've got to relax and go out there and try to execute pitches. Do what you gotta do and give yourself the best chance."
YOU GOTTA SEE THIS With one out and a runner at first in the fourth inning, the Cardinals looked to slow Chen's roll and push some runs across. Martin Prado had other ideas.
On a sharp grounder off the bat of Jedd Gyorko, Prado dove to his right and gloved it behind the bag at third. He bobbled before realizing he could get the lead runner with a force play at second. DeJong would then strike out to end the inning.
HE SAID IT "Obviously, you're not going to sit here and make any kind of decisions quickly after a game. You just won a game, and we wouldn't do anything without talking to him about it." -- Mattingly, on Barraclough's status as closer after he was replaced by Guerra with one out and the bases full in the ninth
UP NEXT Rookie right-hander Pablo Lopez makes his seventh career start at 7:10 p.m. ET on Tuesday. Although he took a loss, Lopez was solid in his last trip to the mound on Thursday in Philadelphia, tossing six strong innings of one-run ball. The Cardinals will counter with Miles Mikolas.